Migration to Godot For UI, Using Godot Rust

[d10sfan]

This will track investigating migrating to godot for the UI. This will still keep using the rust code as close to the way it was as possible.

• cancel clearing cached data -clear the cache for the downloads
• user_env::set_controller_var
• controller support for y axis; scroll for controller and keyboard for license agreement - https://www.reddit.com/r/godot/comments/sa19k9/how_to_scroll_content_in_scrollcontainer_via/
• test on steam deck, laptop with wayland
• manual download - let people provide app_id and then download but stop before running?
• #179
• code cleanup
• handle errors (match on everything in ready, progress errors, etc); send errors through progress channel or main depending on thread; error should just be progress screen without the progress bar and text lines
• UI spacing
• default to controller icons if controller detected at startup
• look into if steam controller test is needed on godot side for showing glyphs and setting controller found env
• fix UI spacing for license agreement (if too large)
• fix first launch (scripteval) causing small window weirdness
• clean up ui to have different scenes with mainscene being control scene
• choices for downloads
• questions implementation (generic like the other as much as possible)
• look at code from old main function and port over to ready?
• handle game without engine choices
• hide godot window once game launches, or just show simple message while it's still there
• handling defaults and setting as default; clearing default choice
• add progress messages for setup (after questions)
• logging not writing out to file?
• all the rest of the missing features (errors on game/setup/download/extract, logging setup, key enter, etc)
• ci changes to build godot and library and package it all together - https://gist.github.com/jjmontesl/60e20dc231e46d218a781f7a8f9cc679; github action should check against godot files
• test performance of install log with large files (like qt5 games); improve scrolling issue, possibly replace transmitting each line with just logging for each install start and completion
• cleanup credits section; readme (use_controller no longer an option; review build local and other instructions)