[Tracker] Improve method and class exports

[Bromeon]

Several issues relate to the#[derive(NativeClass)] macro and in particular the #[export] token. Both currently lack some functionality, that is either already available in GDScript or would simplify the binding to existing Rust data structures.

Class exports

• Derive NativeClass for known monomorphizations of generic types #601
• Rename #[derive(NativeClass)] types #603
• Do not import gdnative types, and use canonical paths in macros #624
• Further static safeguard against creating instances of types with no_constructor in Rust #629
• Re-organize type-level attributes in NativeClass derive macro #848

Method exports

• Rename exported methods #732
• Allow omitting 'owner' in general #850

Property exports

• Specify exported methods as setters and getters in the property attribute #547
• export property with Array typehints #638
• Export enum property with custom int discriminants #764
• Integrate with gdrust macro for easy property and signal exports #715
• Properties cannot be set during debugging (remote scene tree) #825

Documentation and diagnostics

• Better errors when the signature of exported methods are invalid #439
• Add example for exposing Rust types to GDScript, using derive macros and/or wrapper classes #605
• List of methods that can be exported to Godot #672
• Document precise syntax of exporting #769

"Inverse export" (exposing GDScript API in Rust)

• create a macro to create interfaces for externally defined types #200