Add an event facet to People search

[absempere]

From Roopsi:

… can we add the events to the people filter like we have organizations? It feels weird to have “Events Range” then “Events End Year” then “Events Start Year” and no actual events.
Also not sure if start year can go before end year or if that’s how it works.

Let's see if we can make the order make more sense, even if we can't customize facet order.