Support Hot Reloading

[Matt-Is-Confused]

The upcoming Godot 4.2 release will include support for live reloading GDExtensions.
The Godot PR that implemented this is here godotengine/godot#80284
The Godot-cpp implementation can be found here godotengine/godot-cpp#1200

[PadraigK]

In case it helps provide context to anyone:

My experience today (before 4.2) is that it hot reloads everything when I copy in my dylib. The only exception is when I add a new type to the #initSwiftExtension — in that case I need to tell the editor to reload the project manually. I hope the new Godot changes give us that last piece, it would be nice to never need to reload.

[migueldeicaza]

This patch contains:

(a) Upgrade to the 4.2 API
(b) Unrelated: locking for internal table access
(c) Hot-reload support.

https://gist.github.com/migueldeicaza/1884e40a485ade88eff8b4a4c762e0d9

[migueldeicaza]

Splitting the (b) part

[migueldeicaza]

Ok, hot reload is implemented on main, but I have not tested it, would love if someone could take it for a spin.