Restriction of complete package

[darxriggs]

It would be useful to restrict a complete package (even recursively) and just whitelist / mark the public API of a code base as usable. Is there a way to do this with the checker or better use the module system available since Java 9?

Currently it's possible to annotate a package with @Restricted but no restriction is applied then. That's very confusing.

Therefore I suggest to either
a) implement restriction on packages (if possible)
b) apply a @Target annotation on Restricted to prevent its use on packages

[timja]

Implemented here: #13, needs conflicts resolving and re-submitting

[timja]

cc @oleg-nenashev who helped with the other PR: jenkinsci/lib-annotation-indexer#5