Fetch pipeline configuration from configuration URLs

## Problem

GoCD can dynamically configure pipelines from configuration repositories via plugins, such as [gocd-yaml-config-plugin](https://github.com/tomzo/gocd-yaml-config-plugin) and [gocd-json-config-plugin](https://github.com/tomzo/gocd-json-config-plugin). Without the pipeline configuration from these URLs the analysis is incomplete. It is to be expected that configuration errors may hide in such distributed configuration.

## Task

Use the Rest client (see #2) to fetch the JSON or YAML configuration from the repositories and add the configuration to the GoCD model before analysis