Introduce system commands as alternative to meta HTTP endpoints
Pass in cluster name
Use 'BASE TABLE' instead of 'INDEX' when describing a table to stick
with the SQL terminology
Original commit: elastic/x-pack-elasticsearch@600312b8f7
Adds a mode parameter to all SQL-related requests. The mode parameter is used for license checks as well as to define the response content. For now only two modes are supported plain (default) and jdbc. We will add other modes in the future as we add more clients.
Relates elastic/x-pack-elasticsearch#3419
Original commit: elastic/x-pack-elasticsearch@b49ca38d4b