LU-18114 changelog: split "lctl changelog_*" group into subcommands

LU-18114 changelog: split "lctl changelog_*" group into subcommands

Split "lctl changelog_*" command group into subcommands, e.g.
"lctl changelog_register" to "lctl changelog register".
Also, test-framework is modified to verify this patch.

Signed-off-by: Emoly Liu <emoly@whamcloud.com>
Change-Id: Ifd2c92ab3173507084342b7b575c2506e0e4bb9a
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56133
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Frederick Dilger <fdilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>