Fix remote push being added to receiving local repo

When a remote node pushes updated services, it sets the x-repository
header to identify the repo name. The remote node was setting the
remote repo uri instead of setting the local uri. This caused the
receiving node to add the service to its own local repo.
Add support for adding arbitrary data to service

This can be useful for publishing service specific information, such
as credentials or keys for accessing the service. All communications in
polo are cleartext, sensitive data should be encrypted before being
published.
Merge branch 'service-data'