Elasticsearch plugins are traditionally using org.elasticsearch.plugin group, clients are using org.elasticsearch.client, so it makes sense to move all sql pieces and deliverables into org.elasticsearch.sql group. Otherwise, users might get really confused about an artifact named `server` in the group `org.elasticsearch`.
Original commit: elastic/x-pack-elasticsearch@c3a4042040
Too big. Sorry. Some good things though:
1. Share some code between CLI and JDBC. Probably a good thing
at this point, better as we go on, I think.
2. Add round trip tests for all of proto.
3. Remove the `data` member from `QueryInitResponse` and
`QueryPageResponse` so we response serialization is consistent with
everything else.
Original commit: elastic/x-pack-elasticsearch@c6940a32ed
