Add "Hosted" event for project nights, conferences, etc

[mmcelaney]

When hosting an event it should be noted that you didn't just attend, but as a Dev Advocate you actually facilitated the event to happen. This could cover project nights, user group social nights, hackathons, conferences, etc. The numbers of attendees should be considered as directly advocated (like with when you do a presentation) instead of just indirectly advocated (like when you just attend an event as an attendee.)