Block a user at the group level

• Block a user at the group level.
• A group admin can block any user in the group.
• When a user is blocked from a group, they can no longer participate in the group (in all projects, including subgroups). But they can participate in other groups in the GitLab instance.
• A group admin can unblock at any time.
• There is no ability to expire the block automatically. That is out of scope.