Add a map view of the reports

* Adds a map route for the API
* Uses a naming convention for .html, .css and .js files
* Uses leaflet.js for a map.
* Currently using slice to limit the amount of requests to the API.
Add marker clustering for map view

Adds CSS files for MarkerClustering and create clustering points.

In future we should be considering the clustering along adminstrative
boundaries and colouring by functionality.
Rejigged the README file