[New Lint] Forbid using implicit internal APIs

[ZacSweers]

Some libraries use **.internal.** packages to share APIs across artifacts. Let's expand either the denylisted API checker or the restrictcallsto checker to do this check, or possibly make a new one if needed.

Checking this would be easy - it would be an API in a package that contains .internal. and is a PsiCompiledElement (which would indicate that the element is from an external library). Note this wouldn't work for checkDependencies=true though, so something else would need to be in place for that. Maybe if the package doesn't share a common prefix (i.e. com.library.) with the calling package?