LU-10496 tgt: move FMD handling from OFD to target

LU-10496 tgt: move FMD handling from OFD to target

- move ofd/ofd_fmd.c to target/tgt_fmd.c with corresponding
  changes
- add FMD calls to the MDT for Data-on-MDT files
- per-target tunable parameters init/fini
- update related tests to be correctly used with DOM
- make sanity.sh test_36 to work again
- remove target_handle_ping() along with o_ping method in
  obd operations because it is not used anymore. Ping is
  fully handled in tgt_obd_ping()

Signed-off-by: Mikhail Pershin <mpershin@whamcloud.com>
Change-Id: I24280a2a9610d05eb9655c73bb067f94ff251980
Reviewed-on: https://review.whamcloud.com/34190
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Wang Shilong <wshilong@ddn.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>