Merge PR #29116 into master

* refs/pull/29116/head:
	osd: move heartbeat connection cleanup to helper
	osd: break con<->session cycle when removing heartbeat peers
	osd: mark down heartbeat connections on shutdown
	crimson/: move get_mnow() to ShardServices, pass to heartbeat
	crimson/osd: stubs for get_mnow, get_hbstamps
	crimson/osd/heartbeat: adapt to new MOSDPing fields
	crimson/osdmap_service: add get_mnow(), get_up_epoch()
	osd/PeeringState: take HeartbeatStamps refs for current interval
	osd: track clock delta between peer OSDs
	osd: add get_mnow() interface to OSDService, PG, PeeringState
	osd: record startup_time
	osd: some minor refactoring/cleanup in handle_osd_ping

Reviewed-by: Samuel Just <sjust@redhat.com>