Support recurring events
There are events that take place on a yearly basis. The way the platform works now, one would have to:
- migrate the current event to another server, duplicating the costs
- migrate from JSON to MD and store the old page on git (see #5)
- hack the current collections (people_2020, events_2020, people_2021, events_2021)
One approach can be to have the events of older editions on the archive, and have a fresh collection for the calendar itself