This commit adds a schema management tool for the Monasca
configuration database. Apart from the usual OpenStack schema
management tool subcommands (stamp, upgrade, version) it has
two extra subcommands:
* fingerprint: for computing a SHA1 fingerprint of the
currently currently active database schema.
* detect-revision: for identifiying the Alembic revision
(if any) corresponding to a database
schema that was created with one of the
legacy SQL scripts.
The data provided by the detect-revision subcommand can be
used for stamping the database with Alembic version metadata
when transitioning an existing Monasca configuration database
to Alembic based database migrations.
Story: 2001654
Task: 14341
Change-Id: Ibdd877a23ab5d6d1bbf8d83515c0197554098526