backlog/215

This PR implements the issue https://github.com/telefonicaid/fiware-connectors/issues/215
Ummm, you are right. Now the "servicePath" is common to all the sinks, this specific CKAN parameter must be deleted, at least from the documentation. The keypoint is, in order to avoid a big un-revisable PR, within this PR it has been only added the "servicePath" header preprocessing at the `DestinationExtractor` interceptor for destination extraction purposes. After this PR there will be a second one dealing with the usage fo such a header from the resource naming perspective.