### Summary

To reproduce, run these commands where `ns.col` is the name of a collection you do not have installed and the value of `-p` is a valid collection path that exists:

`ansible-galaxy collection list ns.col -p collections/`
`$?`

The output of $? on devel is 0, but since the collection wasn't found it should be 1. The same issue exists for listing specific roles that do not exist.

To fix:
1. [This method](https://github.com/ansible/ansible/blob/stable-2.14/lib/ansible/cli/galaxy.py#L1494-L1502) needs to return the correct exit code from `execute_list_role` and `execute_list_collection`.

2. `execute_list_collection` and `execute_list_role` will need to be fixed to return 1 if a collection/role was requested and not found.
For example, on [this line ](https://github.com/ansible/ansible/blob/stable-2.14/lib/ansible/cli/galaxy.py#L1680) add
```python
        if not collection_found and collection_name:
            return 1
```

3. Add a new test to [this file](https://github.com/ansible/ansible/blob/stable-2.14/test/integration/targets/ansible-galaxy-collection/tasks/list.yml), similar to [this one](https://github.com/ansible/ansible/blob/stable-2.14/test/integration/targets/ansible-galaxy-collection/tasks/list.yml#L111-L116) that lists a single collection that does not exist. Then add an assert task following it to test that the command result's rc is 1.

4. Add a `bugfixes` [changelog fragment](https://docs.ansible.com/ansible/latest/community/development_process.html#creating-a-changelog-fragment).

### Issue Type

Bug Report

### Component Name

ansible-galaxy

### Ansible Version

```console
$ ansible --version
ansible [core 2.15.0.dev0]
```


### Configuration

```console
# if using a version older than ansible-core 2.12 you should omit the '-t all'
$ ansible-config dump --only-changed -t all
```


### OS / Environment

N/A

### Steps to Reproduce

<!--- Paste example playbooks or commands between quotes below -->
```bash (paste below)
ansible-galaxy collection list ns.col -p collections/
$?
```

### Expected Results

1

### Actual Results

```console
0
```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
publish_parser = parser.add_parser('publish', parents=parents,
                                           help='Publish a collection artifact to Ansible Galaxy.')
        publish_parser.set_defaults(func=self.execute_publish)
        publish_parser.add_argument('args', metavar='collection_path',
                                    help='The path to the collection tarball to publish.')
        publish_parser.add_argument('--no-wait', dest='wait', action='store_false', default=True,
                                    help="Don't wait for import validation results.")
        publish_parser.add_argument('--import-timeout', dest='import_timeout', type=int, default=0,
                                    help="The time to wait for the collection import process to finish.")
    def post_process_args(self, options):
        options = super(GalaxyCLI, self).post_process_args(options)
        
        setattr(options, 'validate_certs', (None if options.ignore_certs is None else not options.ignore_certs))
        display.verbosity = options.verbosity
        return options
    def run(self):
        super(GalaxyCLI, self).run()
        self.galaxy = Galaxy()
        def server_config_def(section, key, required, option_type):
            config_def = {
                'description': 'The %s of the %s Galaxy server' % (key, section),
                'ini': [
                    {
                        'section': 'galaxy_server.%s' % section,
                        'key': key,
                    }
                ],
                'env': [
                    {'name': 'ANSIBLE_GALAXY_SERVER_%s_%s' % (section.upper(), key.upper())},
                ],