LU-14165 utils: llog_reader: display changleog_user records

LU-14165 utils: llog_reader: display changleog_user records

Add a function to print changelog_user information.

llog_reader output:

01 (080)changelog user record (v2) id:0x0 cur_id:3 cur_endrec:0
cur_time:1661258371 cur_mask:0x00000003 cur_name:"toto"
...
04 (080)changelog user record (v1) id:0x0 cur_id:6 cur_endrec:0
cur_time:1661261064

Test-Parameters: trivial testlist=sanity,sanity-hsm
Signed-off-by: Etienne AUJAMES <eaujames@ddn.com>
Change-Id: I4e948f52a678127d70e8084e94fb89ec2677cc4b
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/40818
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>