[DocDB] xcluster: Enhanced support for geopartition

[bmatican]

Jira Link: DB-803

Description

Currently, one can setup xcluster between 2 different xclusters, each configured with geopartitioning, provided that both of them have similar eg: the geo partitions map cleanly between then.

We should evaluate what makes sense to do here in practice, as it's unlikely that users would need to setup xcluster between clusters in the exact same regions, eg: source on regions A|B|C and target also on regions A|B|C.
cc @deeps1991

[deeps1991]

One possible suggestion I have is to maintain parity with Backup, where the plan is to support the following:

1. explicitly specify whether or not to backup/restore tablespaces
2. Edit the tablespace configuration at the time of restore at the destination (for xCluster, this could mean at creation time), so that the same tablespace could mean different configurations on the source side vs the target side. This way, the remaining usages of the tablespace could just work.