Allow click and drag to create events on the reservation calendar

[MichaelZhao21]

Is your feature request related to a problem? Please describe.

Although events are easy enough to create with the time dropdown, it would probably be a lot easier to create events directly through the reservation calendar as we can see overlaps.

Describe the solution you'd like

Just like with Google Calendar's click and drag, allow users to do this on the reservation calendar -- click and drag then take them to the edit event page with the values for start/end time already filled in.

Describe alternatives you've considered

If possible, have a popup on the reservation calendar instead of navigating to a whole other page to create the event on. Also, potentially have this feature disabled if the user is not authenticated.

Additional context

N/A

[MichaelZhao21]

For v-6.3, we will simply make this navigate to the edit page with pre-filled content. In the future, we can consider making a Google Calendar-style popup:

[MichaelZhao21]

Update: too complex for v-6.3