Initial query daemon implementation

This is just a new module that exports a runQueryD function, that can
be imported to run a separate thread handling the luxi requests.

Currently it needs access just to the configuration, in the future it
will need access to an RPC runner too.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Agata Murawska <agatamurawska@google.com>