Binary bloat discussion

### Godot version

4.4-dev

### godot-cpp version

4.4-dev

### System information

wasm in particular

### Issue description

This is intended to primarily be a tracking issue looking at ways to reduce the binary size of these extension libraries. Intended to be an open discussion to followup on https://github.com/godotengine/godot-cpp/pull/1621

### Steps to reproduce

Compiling the simplest of extensions, a single file single including a single header results in a 2MB library (**Reviewer EDIT: macos universal library, i.e. 1MB for each architecture**). Example:

```c++
#include
class Example : public Node3D {
GDCLASS(Example, Node3D);

protected:
Vector2 position2;
static void _bind_methods() {
ClassDB::bind_method(D_METHOD("test_position"), &Example::test_position);
};

Vector2 test_position() const {
return position2;
};

Example() { };
virtual ~Example() {};
};

```

### Minimal reproduction project

N/A