Feature request - indeterminate Event.end

[the-moog]

There are use cases where we don't know an event end.
e.g. If the event was a party it is ongoing and we don't know when the party ends.
Currently the Event model requires and end date, though it is barely used by the code (only to generate Occurances)

Suggestion:
Add a 'long grass' end date, e.g. 99 years and a field that indicates this is a best guess.
Then we can update the end date later and fixup the occurances