Delete modules not provided on PUT

When a dashboard is updated and the 'modules' key is present but there
are modules linked to the dashboard that are not provided. Delete them!

This fits with the idea that PUTing a dashboard is pushing the resource
and is idempotent(ish).
Merge pull request #256 from alphagov/delete-modules-on-put

Delete modules not provided on PUT
wip - dir for schema import which will allow common command on deploy
wip start of script, need to generate first. check how used in spotlight...

also add in modules_json generated from spotlight
wip remove old schemas - this is js

add way to run and proper loading too
wip getting there with the real schemas
Working schema updater

What's the deal with dashboards.json? looks like we have nothing
analogous in the whole project. Also, the query formatter is a bit like
the root module schemas but everything is optional? And there are some
other things?

All odd
trying to validate schemas and then validate all modules

- prove it won't cause problems
- also missing anything to validate dashboards themselves - do we need
  to add this too or are validations on fields enough (rather than
  spotlightify dashboard and check?)