Change to use monasca instead of mon

Renamed data_bag from mon_persister to monasca_persister

Also, renamed attributes to appropriate names from the refactor
of removing the persister. Removed attributes no longer used as well

Use the monasca group instead of the persister group so
/var/log/monasca can be reused between components

Change the credential databag from mon_credentials to just credentials

Change-Id: I5bc564ae3763ff05a44cbdc05a4550d627b4b7d2