Refactor rails controllers

Broad changes:
- Configure the list of services through a YAML file under config/services.yml.
- Create a generic Dashboard Controller to generate service's dashboard.
- Simplify routing through the Dashboard Controller.
- Common Controller uses services list.

To create a new dashboard , you need only the following steps:
- Add a new entry for your dashboard at: config/services.yml.
- Create a new view directory.

@maxfliri and @phss