Align modules to follow latest core module style. Prepare new release

[angelbarrera92]

Hi team!

This PR contains minor changes over the nice work @ralgozino did to update the package:

• Adds license checks in the CI
  • Add license headers to all files
• Add 1.19 e2e testing pipeline
• Add cert-manager as a requirement. The cert generated by gatekeeper does not work in >1.19. So using one autogenerated by cert-manager fixes the issue.
• Tune tests
  • Skipping teardown resource (fastest ci)
  • Add new check for gatekeeper audit deployment
  • Deploy new requirements (cert-manager)
• Add auto-release pipeline: Output example: https://github.com/sighupio/fury-kubernetes-opa/releases/tag/v1.2.0-rc5

Pipeline passing: http://ci.sighup.io/sighupio/fury-kubernetes-opa/98/6/1