LU-16771 llite: cache statfs data for projects

LU-16771 llite: cache statfs data for projects

use per-fs rhashtable to cache project-related statfs

Test-Parameters: fstype=ldiskfs testlist=sanity
Test-Parameters: fstype=ldiskfs testlist=sanity-quota
Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I0bcac75afb9ab74535e2c553c575a812116b14d4
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58781
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Sergey Cheremencev <scherementsev@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>