Reset DB migrations

The database schema has been undergoing rapid evolution in the early stages of the project. Once the database and API are relatively stable, we should remove the current database schema migrations and start from scratch. This would require deletion and re-creation of database contents, but some of our current migrations already require an empty database anyway. This would be a breaking change, but from that point onwards we should support full migration of data across schema upgrades.

We should wait for the completion of the transition to per-tenant (rather than per-user) management of stacks and final resolution of how HA should authenticate with nova before making this change.

sdake
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Agree. Work should hold until we sort out how the metadata server should change as well.