rgw: merge of metadata sync fairness

i'd like to congratulate Shilpa, Or, and Eric on the successful merge of https://github.com/ceph/ceph/pull/45958. Eric designed the distributed bidding algorithm back in 2019, and started on its original implementation in cls_lock. Or took over that work early last year, built up a process for testing and measurement, and eventually rewrote the feature in terms of watch/notify. Shilpa took over early this year to finish up the changes to metadata sync, and shepherded the PR through final reviews and testing i'm really happy with the result, and look forward to its use in data sync as well. thanks team!