Adding support for selecting "until" date for Rule

[smnplk]

I think this would be very useful, since the popup only allows you to create ongoing recurrences.

[forrest]

Hey @smnplk this is already being worked on in https://github.com/GetJobber/recurring_select/pull/12. However, the first attempt was not thread safe and we're waiting for an upgraded PR. Going to close this issue to keep the conversation in one place.