LU-16771 llite: add statfs_project tunable

LU-16771 llite: add statfs_project tunable

Add a client tunable and mount option to turn off project-enabled
statfs() if needed, for example to speed up statfs() execution by
avoiding project quota check.

This new llite tunable statfs_project is set to 1 by default (feature
enabled). To turn statfs_project off:

    lctl set_param llite.*.statfs_project=0

Additionally, statfs_project can be disabled at mount time with:

   mount -t lustre -o nostatfs_project ...

Signed-off-by: Stephane Thiell <sthiell@stanford.edu>
Change-Id: I1c3eb27e66b1d05a1c713732dfe0a4d8f7af769f
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/52872
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alexander Boyko <alexander.boyko@hpe.com>
Reviewed-by: Alexander Zarochentsev <alexander.zarochentsev@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>