Introducing Swagger to zeppelin

This PR is about introducing Swagger to Zeppelin

The idea is to have a implementation for describing, producing, consuming, and visualizing zeppelin RESTful service.

 * [x] Add swagger dependencies to zeppelin
 * [x] Add swagger servlet
 * [x] Add swagger-api notation to the actual rest services (ZQL ZAN)
 * [x] Add swagger-ui - with zeppelin colr (bleu)
 * [x] Fix bugs
 * [x] Write test to make sure nothing is broke :smile: