Introduce Recurring Events (2 week ticket)

### Overview
Allow admins to create recurring events.

### Details

Event Creation
- Add a dropdown for recurring events on the event creation modal right under the date row. It should have the following options
> - Does not repeat (default)
> - Daily
> - Weekly on [day of week] (ie: weekly on Wednesday)
- Pass the recurrence information to the backend
- Store if the event isRecurring on the eventParent and then make the necessary events based off the recurrence

Event Edit
- On edit do not allow the recurrence options to be changed in the UI
- If the user only changes the date, then it will just change that event's date
- If the user changes any other item do a popup modal on save that asks the user if the changes should apply to Just this event or All events
- If all events, just change the eventParent data model
- If just this event, create a new eventParent data model with the changes and change this event's eventParentId to the new one (attendance and registrations will stay connected correctly)

Event Delete
- if the eventParent is recurring, show Delete All or Delete just this Event on the delete modal
- If delete All, make sure you delete all the events and the eventParent
- If just this event, just delete the eventId

Future Improvements (don't worry about this right now)
- Allow custom recurrence
- Use https://github.com/ziadadeela/react-recurrence as a jumping off point. We don't need all the options, so I would just copy the pieces we need and make our own components