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.
@goranche I'm totally fine with LOL worthy error message :dog: :) However, I'm not so comfy with leaving the console.log in the code...