Automatic Update Checks on Main Menu Startup

[EraOSBeta]

My Tasks

• [x] Add update checker.
• [x] Add setting to toggle the update check
• [x] Ensure make preflight completes successfully.
• [x] Write PR Description.

Eric Stuff

• [ ] Add a legacy page (http://legacy.ballistica.net/bsLatestBuildNumber) that returns the latest stable/release build number (or the latest beta build number if debug is set to true) as {'build_number': BuildNumberInt}. We can also just add a file to this repository and fetch from that if you don't want to add more stuff to the v1 master server.
• [ ] Add 'Automatically Check for Updates' to the game's built-in config keys with a default value of False.
• [ ] Add and use 3 new Lstrs.
• [ ] Add a CHANGELOG entry.

Description

This PR adds an update checker (disabled by default) to the game. It does not perform any sort of update, however it notifies the player once an update is available (the player will only get notified once per game launch). This is somewhat useful for installs that are not from an app store (Mainly PC installs).

Type of Changes

	Type
✓	:sparkles: New feature