Rename "query info" to "query" everywhere, and "action" to "object"

A "query" here is a request for a specific named object using or not
parameters. This is analogous to a REST (HTTP) GET stateless request:

    GET /path/to/object?param1=value1&param2=value2

Also expect the `metadata-info` object in the ctf.fs query method
instead of the `get-metadata-info` action.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>