Update README and resolve CI Fail

[jswongF5]

Proposed changes

This PR takes care of the following

1. There were questions about including a private Ansible collection in the README which is not needed for this role to work. It was mainly used to document an example of using this role to count the number of NIGNX Plus instances.
2. Resolve CI failure. The NGINX Plus Count CI is failing because Debian 10 is no longer supported. Removing testing this version.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md and CHANGELOG.md)