Events – registration deadline

[kennethrioja]

Is your feature request related to a problem? Please describe

Events are currently sorted by start date, some of the events need registration before – users must be shown when an event is soon to end its registration to be able to properly attend the event.

Describe the solution you'd like

1. In Events class, add 'registration_deadline' (date)
2. In "Upcoming events" of the main page, write the first or the last entry with the closest 'registration deadline'
3. Have a stamp/icon "needs registration" (if 'registration deadline' not blank) and when hovering displays the number of days left to register AND when after the registration date, the stamp/icon is with a red cross
4. Have a filter to show events with 'registration_date' only?

Describe alternatives you've considered

N/A

Additional context

N/A