core: Move getEntityPermissions[ForUserAndGroup]

Moved getEntityPermissions and getEntityPermissionsForUserAndGroups from
DbFacade to PermissionsDAO, where they belong.
Tests were moved from DbFacadeDAOTest to PremissionsDAOTest.

Change-Id: I6085afd4eca6bbd0c5f5ab615d6f06cd242f620a
Signed-off-by: Allon Mureinik <amureini@redhat.com>