Support true multi-tenancy

[krotscheck]

At this point, our multi-tenancy is more "Multi-application" where each application ends up with its own user database. While it technically satisfies the multi-tenancy story, it's not particularly useful if you have to re-create an application for each new tenant.

[krotscheck]

Apparently hibernate already supports some form of multitenancy under the hood. This would, however, also have to apply to search indexes and liquibse migrations.