update among_us: imposter server to support v1.8.0

[QuintenQVD0]

Description

• add the dotnet 7 image as a option as latest version now needs dotnet 7
• move install image to debian 11
• move install script to use our default github release grab script + remove not needed packages
• update egg description as latest version does support more then just 1 client version
• add a note to the version variable that versions start with the letter v

current install script: https://pastebin.com/HHbnLACT

Checklist for all submissions

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Have you tested and reviewed your changes with confidence that everything works?
• Did you branch your changes and PR from that branch and not from your master branch?
  • If not, why?: