Godot: Self-contained mode

[Bobrokus]

Godot can be made self-contained (portable) by creating a ._sc_ or _sc_ file in the installation directory. See the docs and/or the corresponding Github issue.

[Bobrokus]

I'm working on the issue: https://github.com/Bobrokus/scoop-extras/blob/master/bucket/godot.json

Learning from #4566, my goal right now is to add a script for migrating old user data from %appdata%/godot to the persistent editor_data dir. I'll try implementing my amateur approach. If you know pwsh better than me, I'd appreciate it if you'd improve it.