Get details of an Event specified by its id

[etkndr]

• [x] Successful response includes data only for the specified event
• [x] Event data returned includes the id, groupId, venueId, name, description, type, capacity, price, startDate, and endDate
• [x] Event data returned includes aggregate data for numAttending
• [x] Event data returned includes associated Group data, including id, name, private, city, and state
• [x] Event data returned includes associated Venue data, if any, including id, address, city, state, lat, and lng
• [x] Event data returns associated data for EventImages, an array of image data including the id, url, and preview
• [x] Error response with status 404 is given when an event does not exist with the provided id