samba-tool group commands do not handle group names with special chars correctly

Bug: https://bugzilla.samba.org/show_bug.cgi?id=14296

Example:

Creating a group with brackets in its name works:

# samba-tool group add 'samba (R)'
Added group samba (R)

But the delete command does not find the group by its name:

# samba-tool group delete 'samba (R)'
ERROR: Unable to find group "samba (R)"

Other commands like listmembers are also affected.

Use binary encoded group names to fix the affected commands.