Split json from main index.{html,js} files

A new API is introduced (/api/event/list/?format=json), and the index page is changed so it uses the API to retrieve events data. During events data retrieval an animated indicator is shown, and after receiving the data, the map is created and populated.
in general I would disagree on that one (in the case of error logging), but I did forget about browsers without console support...

removing it