Merge PR #70212 into main

* refs/pull/70212/head:
	qa/cephfs-mirror: Fix tests for ISO sync_time_stamp
	doc/cephfs-mirroring: document ISO-8601 sync timestamps
	cephfs_mirror: format sync timestamps as ISO-8601 local time
	tools/cephfs-mirror: report epoch time in last snap sync time

Reviewed-by: Karthik U S <karthik.u.s1@ibm.com>