qa/suites/krbd: add msgr2 modes to most subsuites

qa/suites/krbd: add msgr2 modes to most subsuites

basic, rbd and rbd-nomount subsuites are expanded to run with each
of ms_mode=legacy, ms_mode=crc and ms_mode=secure.  This increases
the total number of jobs in the suite from 100 to 220.

fsx, singleton and thrash subsuites choose ms_mode at random (from
the above plus ms_mode=prefer-crc).

unmap and wac subsuites remain msgr1-only.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
(cherry picked from commit 65948736a41f424d8152b208d013419f8d6038a4)

Conflicts:
	qa/suites/krbd/fsx/conf.yaml [ commit cff2e49ff09e
	  ("qa/suites/krbd: fsx with object-map and fast-diff") and
	  read_from_replica map option not in nautilus ]
	qa/suites/krbd/fsx/ms_mode$/*.yaml [ read_from_replica map option
	  not in nautilus ]