cli: do not use --component in query command, use leftover argument

cli: do not use --component in query command, use leftover argument

Options should be used for optional arguments. In the case of
`babeltrace query`, the component class specification is mandatory,
so use a positional "leftover" argument:

    babeltrace [GEN OPTS] query [OPTS] TYPE.PLUGIN.CLS OBJECT

Example:

    babeltrace query src.ctf.fs trace-info -p 'path="/path/to/trace"'

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