Improve uninstalling NGINX capabilities

[alessfg]

Proposed changes

BREAKING CHANGES:

• The nginx_state variable has been replaced with nginx_setup and instead of using present, absent, latest you should now use install, uninstall and update.
• nginx_install variable is no more. Use nginx_enable instead.

BUG FIXES:

Uninstalling NGINX should now work correctly under most scenarios.

Checklist

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

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