Integrate PR jobs into ci-build.yml

[kaklakariada]

Currently each project using PK must configure branch protection to contain jobs build, next-java-compatibility and linkChecker. To simplify configuration, PK should inline jobs next-java-compatibility and linkChecker into ci-build.yml and make job build depend on these two.

This way, projects only need to add a single job (build) to branch protection.

PK must delete the not needed workflow yml files automatically.

PK must allow customizing the next-java-compatibility job via .project-keeper.yml. Some projects might require special command line options.