DashboardController

Purpose: The Rest API is needed to integrate frontend part of the application with the backend part.

Behaviour: DashboardController class contains GET request handler that responds with the List of BuildInfos fetched from the storage or sets response status to 400 (Bad Request) if the provided path variables are illegal. If the storage is empty or the entries with the given parameters don't exist the empty list is returned.

Sending requests from the front-end: Valid request to the endpoint should be of the following form: /builders/number={number}/offset={offset}, where the number is a non-negative integer that represents the number of database entries to retrieve and the offset is also a non-negative integer that represents the offset from the latest database entry, for which to consider the requested number of entries. For instance, to fetch two entries, starting from the second entry, the following url should be used: /builders/number=2/offset=1

This part of the application was added in this CL.