qa/workunits/rbd: update to mirror group snapshot tests

qa/workunits/rbd: update to mirror group snapshot tests

New tests:
- force promote test with daemon running on both clusters
- test_enable_mirroring_when_duplicate_group_exists
- test_odf_failover_failback test
- test_resync_marker test
- test_force_promote_before_initial_sync test
- scenarios in test_create_group_with_images_then_mirror_with_regular_snapshots

Disabled tests:
- test_force_promote scenarios 2 & 3 which repeatedly fail

Renamed tests:
- test_multiple_user_snapshot_time to test_multiple_mirror_group_snapshot_unlink_time
- test_multiple_user_snapshot_whilst_stopped to test_multiple_mirror_group_snapshot_whilst_stopped

Signed-off-by: John Agombar <agombar@uk.ibm.com>