Part of #67589.

In order to visualize the locks currently held by transactions in a database, as well as the transactions waiting on locks, we will need a virtual table that can call out to the KV interface to query locks (#74833) and display the results. This will be a crdb_internal table, called crdb_locks, that can be joined with existing tables such as cluster_transactions and cluster_queries to visualize what transactions are currently holding or blocked waiting for a particular lock.

Jira issue: CRDB-12288