Frontend for group types

Provide a frontend fo creating group types and connect them to groups

added part::frontend prio::2 type::feature workflow::confirmed labels

assigned to @debdolph

created merge request !270 (merged) to address this issue

mentioned in merge request !270 (merged)

mentioned in commit 468cac28

closed via merge request !270 (merged)

mentioned in merge request Teckids/ticdesk!55