[operator] During operator build make sure CRD files are always generated

In Github actions, when we build the operator we should make sure there are no modified files as part of `make codegen`. If something is not in sync fail the build

Start with the GitHub Actions workflow that builds the operator and run `make codegen` locally to observe whether it modifies files. Add a build check that detects generated-file changes and fails when the repository is not in sync; done means the operator build passes only when `make codegen` leaves no modified files.

Written by the indexing model from the issue text.