Mark `o.h.persister.entity` and `o.h.persister.collection` as internal

Currently, all of the persister implementations are considered public API as they are

1. not in an internal package

2. not annotated as @Internal

Cannot apply to package, so apply for each public type as appropriate.

Also moves AttributeMappingsList and AttributeMappingsMap to the more appropriate org.hibernate.metamodel.mapping package