Calendar is slow and hard to manage

[GrumpyOldTroll]

The events manager is reported hard to navigate when adding events:

• slow to check alternate months when checking for conflicts (as compared to e.g. google calendar),
• time-setting is annoying (scroll wheel that starts at 12:00am is not ideal),
• date-setting is annoying (almost all events are single-day, but you have to set a start and stop date separately)
• recurring events are annoying (it fills the events list management page with repeated spam that makes it hard to find more specific events and outright fails if you make too many, plus you have to specify an unknown end date)
• slow to commit events

[GrumpyOldTroll]

I tried to mitigate this. I'm not that happy with the result, but current status is we have 2 calendars:

• room reservation calendar is now a google calendar, with none of these problems (https://cvuuf.org/blog/rooms-calendar/)
• the wordpress eventmanager plugin is now only for "public events", defined as those where everyone is invited (https://cvuuf.org/blog/events-calendar/). The public events are under half the events that need scheduling, so the UI problems with eventmanager are somewhat reduced.

This also has the benefit of cleaning up the "Upcoming Events" feed at the bottom of the home page, which now lists only the public events (rather than mostly listing committee meetings, which are not going to be useful for non-members of those committees).

However, I'm worried the cure might be worse than the disease, because maintaining 2 calendars will definitely have trouble with synchronization (when public events change, they have to change in both calendars). In addition, the public events still have these problems, but our wonderful volunteer room reservation coordinator no longer has to deal with them, for the most part.

I'm leaving this open because all the same problems are still present for the public events, but the priority is reduced. (Note: this change is the primary way to address https://github.com/CVUUFellowship/church/issues/42)