Add support for restoring managed instance databases to instances in another region

**Is your feature request related to a problem? Please describe.**

The current [api](https://docs.microsoft.com/en-us/rest/api/sql/manageddatabases/createorupdate) will return `SubscriptionDoesNotHaveServer` if the source and destination database are not in the same location.

It is actually possible to do such a thing in the UI.
Go to the target instance -> New database -> Use existing data (Backup) and choose a database from a different region.

**Describe the solution you'd like**
Since it is possible with some other api call via the portal, the cli should be able to do it as well.

**Describe alternatives you've considered**
Don't know much of the internals here to suggest something.

**Additional context**
I have not tried it with PowerShell.