Big update to “Custom Components” documentation, critical localization fix

[DP News-Robot]

I have extended the Custom Components documentation, to serve as a good overview for people who want to create new components that are registered in CGE editor. Nicer introduction and consolidates important information from other pages, Documented publishing classes: using subcomponents, references, observing them using TFreeNotificationObserver Documented when and why you should use SetTransient There’s …