Process to move client between databases

Sponsored by FH we made a plugin that is able to move a complete client from an external database to the current database.

After some discussions we thought this feature is better to have in core, there are a lot of potential usages for that, like:

• common need: implementation started in a test database, and after finishing tests it is needed to move all the tenant with configuration data to production database

• another possibility for the program: migrate tenants from an oracle database to a postgresql database and viceversa

• another possibility: located on a multi-tenant server, extract a single tenant in its own dedicated server