sql: add contended tables, indexes, and keys views

PR: https://github.com/cockroachdb/cockroach/pull/66370

From release notes:
> Added three new views to the `crdb_internal schema` to support developers investigating contention events: `cluster_contended_{tables, indexes, keys}`. [#66370][#66370] {% comment %}doc{% endcomment %}