calendar: Link day label in calendar grid view to scroll the event list to the chosen day

[carrythebanner]

FullCalendar, the library we're using for the grid view, has an option to make each date label clickable. The default implementation is to load that day in the grid's day view, but we could also make it scroll the page to that day's rides in the event list (similar to the classic cal's month view).

Docs: https://fullcalendar.io/docs/date-nav-links

[carrythebanner]

I looked into adding a custom handler with navLinkDayClick option, to scroll the list to the chosen date. I got a start on it, but it needed some more tweaking to work properly so I fell back on FullCalendar's default behavior.

For future reference, I tried this:

navLinkDayClick: function(date) {
  var dateString = moment(date).format("YYYY-MM-DD");
  var heading = document.querySelectorAll("div[data-date='" + dateString + "']")[0];
  heading.scrollIntoView();
}

Needs two improvements at least:

• The date does scroll into view, but usually ends up under the top nav. Needs an offset to account for that.
• All dates are links, whether or not there is something on those dates. If you click an empty date, nothing happens (since the corresponding heading doesn't exist) and it just looks broken.