[Feature Request] Add permission for group bans

[K3RRR]

ISSUE:
I can enable group banning via: settings>features, enabling the feature allows admins to ban an entire steam group if need be. The issue is that all admins can use this feature once it is enabled regardless of immunity, hierarchy or admin group. There seems to be no option to limit it's functionality to a certain group of admins (example: head admins and above).

When I check: groups>web admin groups there seems to be options to edit bans of a group and unban group bans, but no option to add a group ban (refer to image below).

Image shows other group ban options but no add a group ban option:

SOLUTION:
Provide an option to add a group ban as specified in the image below. This will allow us to make certain web groups that allow players to utilize the group banning feature once it is enabled. It seems to have accidentally been overlooked as the other two group options are already there once group banning is enabled.

Image shows added group ban option to rectify the issue:

[rumblefrog]

This is an interesting one since the group ban is directly a tab of the ban page. I think we can block the function being used and display a pop-up error, otherwise, we would have to move the group ban to its own page.

[rumblefrog]

Try this branch: https://github.com/sbpp/sourcebans-pp/tree/add_group_ban_flag (I have not tested it yet)