Adding a menu for pv-addon-groups

[BAD7777]

Currently, managing groups in pv-addon-groups is done through commands, which can be inconvenient for players. I propose adding a GUI menu to simplify the process.

[ImBadInGerman]

Maybe even an API so that other plugins can use it

[Scarlxrdddd]

An API would be great! Manipulate and list group...