Inital part of the new column module.

Can be configured to use max-bars

It's basically the same as a bar-chart-with-number for now however it groups a collection and does some other bits to the collection to get the x-axis working in bar charts.

Updated the controller_map to use the new column module.
Tests for the column visualisation.
Added the ability to add a label to the x-axis of the graph.
Made the default labels for the graph obviously bad so they're implemented in the json.
Add in concept of a `column-graph` to markup

- Adds in a modifier to a `single-decker-graph`, the only change this makes a the moment is to add extra height to the graph, but could be useful for future modifications
- The SCSS is very nested, this is a shame, but probably shouldn't be tackled here
Merge pull request #819 from alphagov/feature/column-module

Feature/column module