Editor: investigate generating Editors and PropertyDrawers with source generation

[jonisavo]

Currently, UIComponents can be used to create components, which can then be instantiated in Editors and PropertyDrawers.

However, it may be possible to provide a way to automatically generate an Editor or PropertyDrawer with an attribute like this:

[EditorFor(typeof(MyBehaviour))]
public class MyBehaviourEditorComponent : UIComponent {}

[PropertyDrawerFor(typeof(MyProperty))]
public class MyPropertyDrawerComponent : UIComponent {}

Whether this is possible and/or a good idea needs to be investigated.