Add Event types

Close #39. Close #38. Close #36. Close #35. Close #30. Add event types. Update events to work with event types. Add tests for event types. Update event tests.
I think our entire routes file is not of good code quality.

I kinda expect this to look something like
```ruby
resources :event_types, controller: "events" do
  delete :__contoller method name here__, on: member
end
```
but im not really an expert in this area so im not sure. I just think using all matches is a bad code smell.