Automatic client updates, planets, and a galaxy map!

Major changes:

- The game now has a launcher that automatically downloads the latest version

- Add planets that can be landed on

- Add a visual galaxy map with "territories" for different factions

Minor changes:

- Remove beacons until they have a use

- If the captain quits the game or disconnects, kick the crew members back to the main menu

If you'd like to read some technical details about the game launcher, check out https://parlette.org/blog/2022/09/automatically-update-godot-game-clients/