Update #1: Bugfixes and "Invert Mouse" option

This is the first update for the game and a relatively small one to fix some current issues and add some quality of life improvements.

Patchnotes:
- FIXED: turret damage no longer counts for the fighter achievements
- FIXED: B2 Attack pod sometimes getting destroyed too early
- FIXED: doors sometimes not closing correctly
- ADDED: link to the games discord in the main menu
- ADDED: "Invert Mouse" option to the settings menu