Ingester Configuration

[gtfierro]

Configuration of the ingester is definitely a sore spot. Some ideas:

• the "schema" field in the message can be used to suggest a plugin, which could then be fetched/loaded and used to archive data. Because of the protobuf-json translation, we could embed jq and have parsing logic defined in terms of jq programs. We aren't currently using the schema field for anything other than xbosproto/XBOS. Could also put this in the XBOS top level message
• the "contextd" daemon saves an RDF representation of published resources. This engine could be integrated into the ingester and used to bootstrap the subscriptions
• add default subscriptions to the ingester.yml file