Godot

Hello, I just wanted to make a small proposal to this wonderful crate. Namely, to improve the ergonomics for when using a custom build of godot.

Problem
The problem is as such, a user wants to use godot-rust with a custom build of godot so they need a custom build of gdnative-bindings to use godot-rust. The current process is nicely documented [here](https://godot-rust.github.io/book/a

it should be saved for consistency of randomness when loading and saving

needs to be compatible with older saves, I put an idea in the TODO comment regarding how to do that.

Currently it looks like that:

We could use a UI theme there. I'd also rather use styleboxes and piggyback on button and similar nodes than use custom textures.

When a player updates their current skin or display name on the options screen while in a game (multiplayer or singleplayer), it should update as soon as the player exits the options screen.