sql/catalog/lease: make lease acquisition concurrency configurable

**Is your feature request related to a problem? Please describe.**
Currently, there is a hard-coded maximum concurrency of lease acquisition per node set to 5. This can cause problems when lease acquisition is extremely slow, as can happen in geo-distributed clusters with very high inter-node latency.

**Describe the solution you'd like**
We should make the concurrency a cluster setting.

**Describe alternatives you've considered**
There are other approaches to reducing the duration of lease acquisition, but they all have some tradeoffs. Making the tables which are read global would likely help a lot. Being thoughtful about replica placement so that the committing quorum on the writes is faster could also help.

Removing the round-trips due to cross-descriptor validation as described in https://github.com/cockroachdb/cockroach/issues/95764 would also help.

Jira issue: CRDB-24337

Epic CRDB-60956