Move to oslo.db

Replace common oslo code nova.openstack.common.db by usage
of oslo.db library and remove common code.

Replaced catching of raw sqlalchemy exceptions by catches
of oslo.db exceptions(such as DBError, DBDuplicateEntry, etc).

Co-Authored-By: Eugeniya Kudryashova  <ekudryashova@mirantis.com>

Closes-Bug: #1364986
Closes-Bug: #1353131
Closes-Bug: #1283987
Closes-Bug: #1274523
Change-Id: I0649539e071b2318ec85ed5d70259c949408e64b
Merge "Move to oslo.db"