Add support for autocompleting/manipulating --query argument

Not sure exactly what this would look like, but I want to:

a) Attempt to autocomplete the JMESPath expression for `--query`. This seems tough.
b) Live update in a vsplit/hsplit pane the result of applying the query expression provided so far against sample generated output.

I demo'd a POC of this with vim + jpterm at re:Invent, would like to have a similar feature as well.

The issue names no files, tests, or implementation entry points. Start by locating handling for the --query argument and the shell's sample-output display, then review the referenced vim + jpterm proof of concept if available. Done would require an agreed design for JMESPath completion and live split-pane query results.

Written by the indexing model from the issue text.