LU-14961 tests: set Pool Quotas

LU-14961 tests: set Pool Quotas

We are interested in running some tests on fs with
pool quotas set for some users. For instance, setting
pool quotas limits for mpiuser allows to stress pool
quotas code with mpi tests.
Patch adds ability to set pool quotas block hard limits
for specific users via POOLS_QUOTA_USERS_SET.
Example:
  POOLS_QUOTA_USERS_SET="quota15_1:20M
                quota15_2:1G:gpool0
                quota15_4:200M:gpool0
                quota15_4:200M:gpool1"
For quota15_1 limit 20M will be set for all existing
pools.

Test-Parameters: env=FS_POOL="glo",POOLS_QUOTA_USERS_SET="mpiuser:200M quota15_1:2000M:glo1",FS_NPOOLS="2",ENABLE_QUOTA="yes"
Signed-off-by: Elena Gryaznova <elena.gryaznova@hpe.com>
HPE-bug-id: LUS-10059
Reviewed-by: Vladimir Saveliev <vlaidimir.saveliev@hpe.com>
Reviewed-by: Sergey Cheremencev <sergey.cheremencev@hpe.com>
Change-Id: Ia9ee540ca77e70f37aa849e5e555e3c057e2052d
Reviewed-on: https://review.whamcloud.com/44740
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>