Clipboard Narrator v1

With Godot 4 stable being out it's time for the first release of clipboard narrator!

I only added a binary for Windows because on Linux you need to install text-to-speech libraries and there is currently no error when they are missing outside of running the project through the editor. And Mac export gives warnings about Gatekeeper so you may as well just export it yourself I guess?

Documentation for which libraries you need on each distro should eventually be available: godotengine/godot-docs#5823.

It does not seem that they'll be added to Godot itself godotengine/godot#67863 (comment) but there's still an open issue for it here: godotengine/buildroot#7.