LU-17848 dt: allow dio_lookup/insert/delete to be optional

LU-17848 dt: allow dio_lookup/insert/delete to be optional

Not every user of the dio API require these operations. Return
EOPNOTSUPP rather than LASSERT() if they are not implemented.

Clean up some stub functions in osp and lfsck.

Test-Parameters: trivial
Test-Parameters: trivial fstype=zfs
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: I2df23b87cfca5844f8c5ca843251c463909fcd47
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55633
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>