LU-16524 nodemap: add rbac property to nodemap

LU-16524 nodemap: add rbac property to nodemap

Add new rbac property to nodemap. Internally this is a mask of allowed
roles. Externally it defaults to all, which means all roles are
allowed, and it can take the following values (multiple can be
specified, comma separated), with the semantic:
- byfid_ops, to allow operations by FID (e.g. 'lfs rmfid').
- chlg_ops, to allow access to Lustre Changelogs.
- dne_ops, to allow operations related to DNE (e.g. 'lfs mkdir').
- file_perms, to allow modifications of file permissions and owners.
- quota_ops, to allow quota modifications.
Apart from all, any role not explicitly specified is forbidden. And to
forbid all roles, use 'none' value.

Update lctl-nodemap-modify man page to mention this new property.

Lustre-change: https://review.whamcloud.com/49873
Lustre-commit: 5e48ffca322c3c72d3b83b0719f245fc6f13c8e4

Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I4cedf03c75948f4b1e9b55292414ab9110701874
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/50293
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>