feat: on action decorator

[sveneberth]

Usage

class MyModule(List):
    @on_edited
    @on_added
    def entry_observer(self, skel):
        print(f"Entry changed: {skel = }")

What do u think of this concept?

[phorward]

What do u think of this concept?

Quite interesting. This looks like a more dynamic replacement for #972.
But I would like to combine it with the meaning of actions. So an action is defined once, and generates hooks, access, access-right etc. via one definition.