### Summary

The `apt_repository` will fail with a somewhat confusing error if gnugp, and dirmngr manager are not installed.  Neither of these packages are Required/Essential/Important, and may not be already installed in minimal systems that you might want to run `apt_repository` on.

The fix might be to just include `gnupg` in the requirements section of the docs.

### Issue Type

Documentation Report

### Component Name

apt_repository

### Ansible Version

```console
$  ansible --version
ansible [core 2.11.4]
  config file = ...
  configured module search path = ...
  ansible python module location = ...
  ansible collection location = ...
  executable location = /usr/local/bin/ansible
  python version = 3.9.2 (default, Feb 28 2021, 17:03:44) [GCC 10.2.1 20210110]
  jinja version = 3.0.1
  libyaml = True
```


### Configuration

```console
$ ansible-config dump --only-changed
```


### OS / Environment

Mostly a docs issue so this is N/A. But apt_repository applies to Debian, Ubuntu, and forks.

### Additional Information

Tells people that need gnupg when using apt_repository.

### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
apt_pkg_name = 'python3-apt' if PY3 else 'python-apt'
        if has_respawned():
            
            module.fail_json(msg="{0} must be installed and visible from {1}.".format(apt_pkg_name, sys.executable))
        interpreters = ['/usr/bin/python3', '/usr/bin/python2', '/usr/bin/python']
        interpreter = probe_interpreters_for_module(interpreters, 'apt')
        if interpreter:
            
            respawn_module(interpreter)
            
        
        if module.check_mode:
            module.fail_json(msg="%s must be installed to use check mode. "
                                 "If run normally this module can auto-install it." % apt_pkg_name)
        if params['install_python_apt']:
            install_python_apt(module, apt_pkg_name)
        else:
            module.fail_json(msg='%s is not installed, and install_python_apt is False' % apt_pkg_name)
        
        interpreter = probe_interpreters_for_module(interpreters, 'apt')
        if interpreter:
            
            
            respawn_module(interpreter)