Gamepad support for launcher

[MisterSheeple]

Is your feature request related to a problem? Please describe.
The experience is unintuitive on Steam Deck because it requires either a mouse or using the touch screen to launch into the game.

Describe the solution you'd like
Simple gamepad support for the launcher UI would go a long way for accessibility on Steam Deck and other console-like hardware.

Describe alternatives you've considered
Manually mapping inputs using Steam Input is an option, but it's not ideal and shouldn't be a permanent solution.