limithandler: Log queue duration in limit.concurrency_queue_ms log field
In the same vein as !5330 (merged) and !5332 (merged).
We currently have no per-RPC stats on how long an RPC spent in the concurrency limiter. This MR introduces that capability by adding a limit.queue_ms
field to the logs.
It required jumping through some hoops due to middleware ordering. I can add a more comprehensive test case similar to commandstatshandler_test
if desired.
Edited by Igor