Add tags for 'prepare' and 'verify' stages to help the testing of OSM version migration. New Keyword to get ns_id from NS name so that the tests with 'verify' tag can be executed in isolation.

Change-Id: I3f199146a8dbbe2f5f6aeb26a10b95440ee74470
Signed-off-by: rodriguezgar <frodriguezg@indra.es>