[ansible/artifactory_nginx] refactoring of artifactory_nginx role

[EmptyByte]

PR Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• [x] Title of the PR starts with installer/product name (e.g. [ansible/artifactory])
• [ ] CHANGELOG.md updated
• [x] Variables and other changes are documented in the README.md

What this PR does / why we need it: Refactor the artifactory_nginx ansible role and removes the requirement of a sub-sub-role. It is now more modular. By default it does not configure nginx repositories unless explicitly requested with: artifactory_nginx_use_official_repos: true

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes # N/A

Special notes for your reviewer: N/A

[github-actions[bot]]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[EmptyByte]

I have read the CLA Document and I hereby sign the CLA

[vasukinjfrog]

Review in Progress