##### SUMMARY

The list subcommand throws a lot of warnings about a missing version if the collection was not built and installed via an artifact. This information can often be obtained in the galaxy.yml though, so it would make sense to fallback to that ...

```
(ansible_base) [vagrant@centos8 ~]$ ansible-galaxy collection list
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/azure/azcollection' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/cyberark/bizdev' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/google/cloud' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/netbox_community/ansible_modules' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/splunk/enterprise_security' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/ansible/netcommon' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/check_point/mgmt' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/f5networks/f5_modules' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/ibm/qradar' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/openstack/cloud' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/vyos/vyos' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/arista/eos' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/cisco/iosxr' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/cisco/ucs' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/cisco/aci' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/cisco/meraki' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/cisco/intersight' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/cisco/mso' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/cisco/ios' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/cisco/nxos' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/fortinet/fortios' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/junipernetworks/junos' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/purestorage/flasharray' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/purestorage/flashblade' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/awx/awx' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/community/grafana' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/community/kubernetes' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/community/amazon' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/community/vmware' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/community/general' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/gavinfish/azuretest' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/netapp/aws' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/netapp/elementsw' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/netapp/ontap' does not have a MANIFEST.json file, cannot detect version.
[WARNING]: Collection at '/home/vagrant/.ansible/collections/ansible_collections/servicenow/servicenow' does not have a MANIFEST.json file, cannot detect version.

# /home/vagrant/.ansible/collections/ansible_collections
Collection                       Version
-------------------------------- -------
ansible.netcommon                *      
arista.eos                       *      
awx.awx                          *      
azure.azcollection               *      
check_point.mgmt                 *      
cisco.aci                        *      
cisco.intersight                 *      
cisco.ios                        *      
cisco.iosxr                      *      
cisco.meraki                     *      
cisco.mso                        *      
cisco.nxos                       *      
cisco.ucs                        *      
community.amazon                 *      
community.general                *      
community.grafana                *      
community.kubernetes             *      
community.vmware                 *      
cyberark.bizdev                  *      
f5networks.f5_modules            *      
fortinet.fortios                 *      
gavinfish.azuretest              *      
google.cloud                     *      
ibm.qradar                       *      
junipernetworks.junos            *      
netapp.aws                       *      
netapp.elementsw                 *      
netapp.ontap                     *      
netbox_community.ansible_modules *      
openstack.cloud                  *      
purestorage.flasharray           *      
purestorage.flashblade           *      
servicenow.servicenow            *      
splunk.enterprise_security       *      
vyos.vyos                        *
```


##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
ansible-galaxy collection list

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
devel
```


raise AnsibleError("The collection galaxy.yml at '%s' is missing the following mandatory keys: %s"
                           % (to_native(b_galaxy_yml_path), ", ".join(sorted(missing_keys))))
    extra_keys = set_keys.difference(all_keys)
    if len(extra_keys) > 0:
        display.warning("Found unknown keys in collection galaxy.yml at '%s': %s"
                        % (to_text(b_galaxy_yml_path), ", ".join(extra_keys)))
    
    for optional_string in string_keys:
        if optional_string not in galaxy_yml:
            galaxy_yml[optional_string] = None
    for optional_list in list_keys:
        list_val = galaxy_yml.get(optional_list, None)
        if list_val is None:
            galaxy_yml[optional_list] = []
        elif not isinstance(list_val, list):
            galaxy_yml[optional_list] = [list_val]
    for optional_dict in dict_keys:
        if optional_dict not in galaxy_yml:
            galaxy_yml[optional_dict] = {}
    
    galaxy_yml['license_ids'] = galaxy_yml['license']
    del galaxy_yml['license']
    return galaxy_yml
def _build_files_manifest(b_collection_path, namespace, name, ignore_patterns):
    
    
    b_ignore_patterns = [
        b'galaxy.yml',
        b'.git',
        b'*.pyc',