Remove deprecated index related classes.
Moving compat to depend on core
Tearing down compat

Leaving events only for now
[NEXUS-5971] remove use of ExtensionPoint
Events redirected.

This change affects only EventInspectors! All the other EventBus users
subscribers are still safe
Remove deprecated classes.
Remove nexus-compat module
NEXUS-5971: drop custom guice-nexus scanning/binding code and re-implement @RepositoryType support (simplified)