chore: add GUT test framework

addons/gut/project.godot

@@ -0,0 +1,43 @@
+; Engine configuration file.
+; It's best edited using the editor UI and not directly,
+; since the parameters that go here are not all obvious.
+;
+; Format:
+;   [section] ; section goes between []
+;   param=value ; assign values to parameters
+
+config_version=5
+
+[application]
+
+config/name="Gut"
+run/main_scene="res://scenes/main.tscn"
+config/features=PackedStringArray("4.6")
+config/icon="res://icon.png"
+
+[autoload]
+
+global="*res://scripts/global.gd"
+
+[debug]
+
+gdscript/warnings/redundant_await=0
+
+[display]
+
+window/stretch/mode="canvas_items"
+window/dpi/allow_hidpi=false
+
+[editor_plugins]
+
+disabled=PackedStringArray("res://addons/gut/plugin.cfg")
+enabled=PackedStringArray("res://addons/gut/plugin.cfg", "res://addons/plugin_restarter/plugin.cfg")
+
+[network]
+
+limits/debugger_stdout/max_chars_per_second=8192
+
+[rendering]
+
+textures/vram_compression/import_etc2_astc=true
+environment/default_environment="res://default_env.tres"