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

The process of creating a new sqlliveness session today involves a single Put operation to the system.sqlliveness table. Proving a record is invalid requires scanning the table. Today, the table has no zone configurations so can be in any region.

Describe the solution you'd like

In order to reduce the server cold-start time, we'd like to change the table to be regional by row so that we perform a write to the table without having to wait for multi-region round-trips.

Additional context

In order to make this happen, we'll need to allow regional-by-row tables in the system database.

Part of #85612

Epic: CRDB-18596

Jira issue: CRDB-18410