This commit removes Hibernate imports from JpaProperties so that it can
be used with another JPA provider.

This commit is a breaking change for an internal, yet public class used
to transmit customizations provided by the user. It does not change the
external functionality though: naming strategies defined as bean are
still taken into account and a customizer has a chance to override it
regardless.

Closes gh-13043

See gh-12934

Fixes gh-12807

Fixes gh-12934

Closes gh-13075

Closes gh-13074

Closes gh-13073

Closes gh-13072

Closes gh-13071

Closes gh-13070

Closes gh-13069

Closes gh-13068

Closes gh-13067

See gh-13056

This commit restructures the Cache auto-configuration to avoid an early
init on CacheManager (and potentially all its infrastructure). Rather
than adding a dependency on the validator bean, this commit relies on
the fact CacheAspectSupport checks if a CacheManager is available in the
afterSingletonsInstantiated callback. In this case, a simple bean with
a postconstruct callback is enough.

Closes gh-13038