Content dashboards shouldnt appear in service list

At the moment the list of services includes all dashboards, which means
the numbers on the homepage don't add up and we are showing non-service
dashboards in the list of service dashboards.

I've renamed services.json to dashboards.json as this more truely
conveys what it is. This change knocks on into the collection.

I've made filterDashboards able to accept an array so that we can store
a list of dashboard-types which are 'services' and reference that
constant in any code that wants to filter all services.
Move dashboards into experimental/

These dashboards are new and unready for release to production. Being in
the experimental directory means that the dashboards will not appear on
the homepage or services list.
Merge pull request #482 from alphagov/bugfix/services-list-shouldnt-have-content

Content dashboards shouldnt appear in service list
Merge pull request #483 from alphagov/bugfix/move-new-dashboards-to-experimental

Move dashboards into experimental/
Show departmental acronyms in services list.

Add acronyms for existing services, which were missing them.

No tests since there's no logic, just display - shout if you
think this is wrong.

Pivotal story: https://www.pivotaltracker.com/s/projects/911874/stories/70840458
Merge pull request #484 from alphagov/feature/add-dept-acronyms-to-filtered-service-list

Show departmental acronyms in services list.