Improve design of calendar event

[rotkehlxen]

The calendar events could look better. The timestamp of rise/set time in the calendar event title is probably unnecessary/redundant, because the timestamp is already shown by default (or can that look different on different devices?)

[rotkehlxen]

needs a bit more of investigation. Because apparently it can look very different in another calendar application (to which it was imported from an ics file). For example in Calendar on Mac we don't see the timestamp twice.