Integrate template export with the tpz format of Godot Engine

[fire]

If we can match the .tpz layout we can reuse the godot engine export uiux.

Edited:

See https://github.com/godotengine/godot-builds/releases/download/4.4-dev6/Godot_v4.4-dev6_export_templates.tpz

[fire]

version.txt matches version.py exactly. https://github.com/V-Sekai/world-godot/blob/main/godot/version.py

[fire]

We agree exporting to the tpz executable format should be done in the justfile