Provide a way for hook event to customize its name

[Rarst]

I currently suffix reoccurring events with a number, though what I really wanted to implement for these is meaningful dynamic name generation.

I postponed this because I didn't feel I have a good take and didn't want to complicate new (and much cleaner) hook event configuration format.

Still this is something that should probably happen and challenges are it would need a (potentially complex) callback, as well as access to non-first argument of the hook.

Tentatively I think about moving in direction of configuration objects (either directly created or intermediary generated from flat array configuration) with distinct interfaces, let's say mandatory Boundary for determining start/stop of the event and optional Name for processing hook arguments and generating a dynamic name.