Register user for event

[shanekim28]

ACTION	ROUTE	VERB	DESCRIPTION
CREATE	/api/events/event/{id}/register	POST	Register user for event
UPDATE	/api/events/event/{id}/registration/{registrationId}	PATCH	Update user's event registration status

table EventRegistrations {
  id guid [pk]
  studentid guid [fk]
  eventid guid [fk]
  userstatus varchar
  isresumesanitized bool
  
  Indexes { eventid }
}

If event requires an application, then set userstatus to "applied" or something along those lines