This PR introduces Alembic database migration tool. Trove currently
uses sqlalchemy-migrate with which SQLAlchemy-2.0 does not work. By
introducing the new migration tool, we can prepare for migrating
to SQLAlchemy-2.0.
This change will not affect the default trove-manage's usage while
the database schema versioning will be changed because alembic uses
non-linear, dependency-graph versioning while sqlalchemy-migrate
uses integer based versioning.
Depends-On: https://review.opendev.org/c/openstack/trove-tempest-plugin/+/921589
Co-Authored-By: wu.chunyang <wchy1001@gmail.com>
Story: 2010922
Task: 48782
Change-Id: Idd63f470a2b941720314b6356fe28cd8e394427e
114601edba