cephfs: expand auth/mon configuration options

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
Merge branch 'cephfs/wip-4484' into cephfs/branch-1.0

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
Reviewed-by: Joe Buck <jbbuck@gmail.com>