Redesign the application to be more like an overlay

[oceantume]

With the new Transparent feature, the application is starting to behave like an overlay, but a somewhat ugly one. I've started thinking about making a new UI which may be better suited for it so if you have some suggestions for what that could look and behave like, do let me know here or on discord.

I'm thinking about making a main window for settings that looks like the current one, and then having a second overlay-like UI that would sit on top of the game when active.