Add the flatten option for bar chart with numbers

Module appears to work in exactly the same way after doing this
Merge pull request #844 from alphagov/feature/flat-data-for-bar-chart-with-numbers

Add the flatten option for bar chart with numbers
Add `flatten:true` to query-params of applications collection
Add example and barebones schema for applications module

- Slightly self-referential development stub
- Adds `'applications'` as legit module to run schemas against on startup