'Planned' view shows confusing (start) date for calendar events spanning multiple days with time range

[Gert-dev]

Describe the bug
If you have a calendar event that spans multiple days and a start and end time, the 'Planned' view shows (only) the start time on each day the event is planned, which is confusing.

To Reproduce
Steps to reproduce the behavior:

1. Create a calendar event (e.g. using GNOME Calendar) that spans tomorrow 15:00 to the day after 01:00 (AM).
2. Start Planify.
3. Open the 'Planned' view.
4. Observe tomorrow mentioning the calendar event with time 15:00 (correct).
5. Observe the day after tomorrow mentioning the same calendar event (correct) with time 15:00 (confusing).

Expected behavior
It would probably be strange to show the end time on the last day. It's probably best to show the time range the event applies that specific day instead of just the start time. This will also cater towards events that span more than two days, i.e. where day 1 has a start time, day 2 spans the whole day, and day 3 has an end time.

If there is no time (i.e. the event spans the whole day), one could say 'Whole day' or just not mention the time at all, which is nicer than saying 00:00 - 23:59 or similar.

Desktop (please complete the following information):

• OS or DE: GNOME 49
• Version: 4.17.0