sql: subject `TemporarySchemaCleaner` to admission control

Release note (bug fix): cleanup of temporary schema objects (e.g.
temporary tables) are now subject to admission control, to prevent them
from overloading the storage engine.

ui: update cluster-ui version to 21.2.5

Update cluster-ui version to match published npm version.

Release note: None

Merge pull request cockroachdb#78219 from cockroachdb/blathers/backpo…

…rt-release-22.1-77965

release-22.1: ccl/sqlproxyccl: rename RequestTransfer to TransferConnection, and make it sync

v22.1.0-prerelease-4

v21.2.4

roachtest: remove some configs in tpch_concurrency

This commit removes two out of three configs of `tpch_concurrency`
roachtest since I no longer see much value in running with non-default
txn stats sampling rate nor with admission control disabled.

Release note: None

Release justification: testing only change.

Merge cockroachdb#77159

77159: roachtest/tests: move prometheus client interface to separate package r=ajwerner a=ajwerner

This way mockgen does not depend on the `roachtest/tests` package.

Touches cockroachdb#76851.

Release justification: non-production code change

Release note: None

Co-authored-by: Andrew Werner <[email protected]>

Merge pull request cockroachdb#77490 from aayushshah15/backport21.2-7…

…7246

Merge cockroachdb#38309 cockroachdb#76909

38309: docs: add an Insights into Constraint Conformance RFC r=andreimatei a=andreimatei

The set of features described here aim to provide admins with visibility into
aspects of replication and replica placement. In particular admins will be able
to access a report that details which replication constraints are violated.

Release justification: non-code change
Release note: None

76909: settings: disallow tenant from changing overridden settings r=ajwerner a=RaduBerinde

Informs cockroachdb#73857.

#### settings: simplify default overrides

This commit cleans up the Override() implementation, using a
single `map[slotIdx]interface{}`.

Release note: None

#### settings: disallow tenant from changing overridden settings

We now produce an error if a tenant tries to change a cluster setting
that is currently overridden by the operator. The previous behavior
was too subtle: we would change the tenant's "opinion" on the setting,
which would only take effect if/when the operator override was
removed.

To achieve this we query the settings watcher which always has the
current list of overrides. In the future, we should somehow integrate
this information in `settings.Values`.

Release justification: bug fixes and low-risk updates to new functionality

Release note: None

Co-authored-by: Andrei Matei <[email protected]>
Co-authored-by: Radu Berinde <[email protected]>

Merge pull request cockroachdb#77074 from rail/backport21.1-77038

release-21.1: release: enable bincheck for tag pushes