packages assertions

[xenoterracide]

I'd like to be able to look for annotations on package-info and honestly module-info but that's less important since I have less of those and they are created less often.

packages().should().beAnnotatedWithOneOf(Nullmarked.class, NullUnmarked.class).check(javaClasses);
packages().matching(".*").should().beAnnotatedWithOneOf(InfrastructureLayer.class, DomainLayer.class).check(javaClasses);
packages().matching("..").should().notHaveNestedPackagesDeeperThan(2).check(javaClasses);