LU-11648 mgs: Create white list for CONFIGS directory files

LU-11648 mgs: Create white list for CONFIGS directory files

Not all files that are stored in CONFIGS directory should
be processed. For example there are ".bak" files which
created during change_nids operation and used to store
non-modified copy. Currently blacklist is used to process
CONFIGS directory (".bak"s are excluded), but using
whitelist looks more robust.

These files(patterns) should be in the white list:

*-client
*-MDT????
*-OST????
mountdata
nodemap
params
sptlrpc

Test-Parameters: testlist=conf-sanity
Change-Id: I34871fa11d50941450233053446c6c41a1f83048
Signed-off-by: Artem Blagodarenko <ablagodarenko@ddn.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/57271
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Sergey Cheremencev <scherementsev@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>