### Summary

`ansible-galaxy collection install` makes a lot of requests to galaxy.ansible.com and can occasionally hit the rate limit. When that happens, galaxy.ansible.com will return a 520 http code and `ansible-galaxy` fails to download the collection and exits. Ideally when the client encounters a rate limiting http code (either 520, or 429), it should wait, slow down the request rate and try again rather than exiting.

More information is available here: https://github.com/ansible/galaxy/issues/2429 

### Issue Type

Bug Report

### Component Name

ansible-galaxy

### Ansible Version

```console
$ ansible --version
root@ubuntu-s-1vcpu-1gb-nyc3-01:~# ansible --version
ansible 2.10.7
  config file = None
  configured module search path = ['/root/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/local/lib/python3.8/dist-packages/ansible
  executable location = /usr/local/bin/ansible
  python version = 3.8.5 (default, Jan 27 2021, 15:41:15) [GCC 9.3.0]
```


### Configuration

```console
$ ansible-config dump --only-changed
root@ubuntu-s-1vcpu-1gb-nyc3-01:~# ansible-config dump --only-changed
root@ubuntu-s-1vcpu-1gb-nyc3-01:~#
```


### OS / Environment

All

### Steps to Reproduce

Run `ansible-galaxy collection install `amazon.aws`. If your internet is fast enough, this will occasionally fail when galaxy.ansible.com returns a 520 error code.

### Expected Results

Collection should be installed.

### Actual Results

```console
`ansible-galaxy` encounters a 429 or 520 http code and exits.
```


### Code of Conduct

I agree to follow the Ansible Code of Conduct


url = _urljoin(self.api_server, self.available_api_versions['v1'], "notification_secrets")
        data = self._call_galaxy(url, auth_required=True)
        return data
    @g_connect(['v1'])
    def remove_secret(self, secret_id):
        url = _urljoin(self.api_server, self.available_api_versions['v1'], "notification_secrets", secret_id) + '/'
        data = self._call_galaxy(url, auth_required=True, method='DELETE')
        return data
    @g_connect(['v1'])
    def delete_role(self, github_user, github_repo):
        url = _urljoin(self.api_server, self.available_api_versions['v1'], "removerole",
                       "?github_user=%s&github_repo=%s" % (github_user, github_repo))
        data = self._call_galaxy(url, auth_required=True, method='DELETE')
        return data
    
    @g_connect(['v2', 'v3'])
    def publish_collection(self, collection_path):
        """
        Publishes a collection to a Galaxy server and returns the import task URI.
        :param collection_path: The path to the collection tarball to publish.
        :return: The import task URI that contains the import results.
        """
        display.display("Publishing collection artifact '%s' to %s %s" % (collection_path, self.name, self.api_server))
        b_collection_path = to_bytes(collection_path, errors='surrogate_or_strict')