Include Devise for IPO authentication and StudentApplicationForm

**Please make sure to run 'bundle install', migrations and restart your server**

### Summary: 
  - Adapt devise to work with Refinery and IPO:
     - So now there's only one authentication framework used by IPO Login model (for the students and field hosts) and Refinery::User (the default authentication model used by Refinery::CMS)
     - Include devise views: I had to change the devise routes to be more specific (p.e. `session_path` to `login_session_path`). I didn't change all the devise routes just the ones need it to make a new registration and the sessions to work properly
  - Refactor of StudentFormApplication based on this [branch](https://github.com/ipoconnection/ipo-web/tree/dev)
  - Back to haml! 
  - Use locales in projects/setup and students/setup
  - Basic specs for models
  - Structure for dashboards (field host and student)
  - Home page search feed project search.

### Notes
 - When a project is created some project sessions are created as well (this is temporal, since the project_session form is not defined yet)