Use published flag in our tools script

We are now using a published boolean in the dashboard config to denote
its visiblity from the homepage. This has been reflected in the folowing
tools:

  - Schema validation:
    + I've added the published boolean into the schema
    + It now uses a glob which will pull out all json files from the
      stub/responses dir. It will then filter out !dashboard files once
      it has parsed the JSON. This includes filtering out unpublished
      dashboards, unless the --unpublished flag is passed in.

  - Generate services list:
    + It pulls in all json files, filters for dashboards and then
      whether they have published set to true.

  - Generate module stubs:
    + Pulls in all json files and then filters for dashboards (we no
      longer assume that dashboards are only in the root of responses/)

  - Transactions explorer dashboard generator:
    + Adds published: true to all dashboards