Move hibernate-commons-annotations into a separate module that hibernate search can also use

This jar file is used by several other projects which don't need Hibernate as a dependency; if we don't split it we will either have duplicate jars, (and in the case of Hibernate Search even possible conflicts) or all these modules will need to include Hibernate, getting then bound to a specific version for a long time (while support times don't match).

As a welcome side-effect, applications depending on Hibernate won't be able to see this module, which is a good thing as this is not intended to be a public API.