DATAREST-316 - UriStringDeserializer now guards against UriTemplate.

We now defensively guard against URI templates submitted for related resources and expand the incoming URI string source to avoid URI.create(…) to fail.

Also, RepositoryPropertyReferenceController.loadPropertyValue(…) now also uses UriTemplate to guard against Uri templates provided for property references.
DATAREST-318 - BaseUri now correctly strips template variables from request.

Bugfix in BaseUri to correctly strip template variables when the repository lookup path is obtained from a NativeWebRequest.