Description of problem:
sometimes it can be useful to subscribe to all events available and filter on the receiving end instead of on the sender, but that is not possible today

Version-Release number of selected component (if applicable):
any

How reproducible:
100%

Steps to Reproduce:
1. try to create a webhook that subscribes to more than one event (or "*")

Actual results:
not possible

Expected results:
possible

Additional info: