LU-8626 hsm: count the number of started requests of each type

LU-8626 hsm: count the number of started requests of each type

Add counters in the coordinator to keep track of how many started hsm
requests of each type (ARCHIVE, RESTORE, REMOVE) the coordinator is
managing. There is no counter for CANCEL requests as the coordinator
does not keep track of them like it does for the other requests.

Test-Parameters: trivial testlist=sanity-hsm
Signed-off-by: Quentin Bouget <quentin.bouget@cea.fr>
Change-Id: I0c1e9881f2f6a4f005dfc3545b1b51714eb91b7b
Reviewed-on: https://review.whamcloud.com/28677
Reviewed-by: Henri Doreau <henri.doreau@cea.fr>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Stephan Thiell <sthiell@stanford.edu>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>