learning circles

coordinate study groups for online courses

Remove feedback (learning circle summary) from weekly reflection form

Remove meeting summary, make relection optional, update task logic for sending reminders, update meeting table

Remove notification sent to facilitator when a reminder was generated

Update meeting validation to convert date and time strings to proper Python objects

Move reminder generation logic out of scheduled task function body

Revert updates to meeting change notification. It first needs to be translated.

Revert updates to learner messages so we can release scheduling updates without breaking translations