Merge branch 'httpapi'

This branch provides first version of Boruta REST API. It maps
functionality of Requests, Workers and Superviser interface. There is
also API aggregation package which will make it possible to run multiple
API version simultaneously. Generic Boruta HTTP types and functions are
provided in separate package and may be reused by Boruta HTTP client
package.

Change-Id: I9127f1f9f3681fd3b8037b316acc921098dcb773