Currently, the partition is configured internally by each store when creating or searching identity types.

This behavior is fine for those stores supporting partition management, but for those that don't support we need to handle that differently.

As an example, the LDAP store does not support partition. So we need to always set the default partition for any identity type managed by this store.

If partition is not supported at all, the PartitionManager will always return the default partition (without an id, of course) instance, which holds always the same name (default).

We also need to warn users about this behavior, because this can be a misconfiguration.

This issue is specially important when working with multiple stores supporting different identity types and relationships. In this case, we can have a mix of stores where only one of them is actually supporting partitions, so we need to always consider that the identity types managed by a store without partition management always belong to the default partition.