Add support for properties

[dazKind]

Add a macro implementation here to build and register properties via @:property-metadata here: https://github.com/dazKind/hxgodot-cpp/blob/main/src/godot/macros/Macros.hx#L351

Bonus: use metadata to specify a Property (Sub-)group and default value.
Rough idea:

See

• https://github.com/godotengine/godot-headers/blob/0c542567a900e474dcf6312cc97500168bec0c74/godot/gdnative_interface.h#L541
• https://github.com/godotengine/godot-headers/blob/0c542567a900e474dcf6312cc97500168bec0c74/godot/gdnative_interface.h#L542
• https://github.com/godotengine/godot-headers/blob/0c542567a900e474dcf6312cc97500168bec0c74/godot/gdnative_interface.h#L543

[dazKind]

https://twitter.com/dazKind/status/1570083668726611968