Tests: add a recording rule listing test

Add a test that validates that recording rules can be added to a channel
and listed back. Most of the changes are to the lttngtest package in
order to provide the requisite capabilities to the test itself.

This test is also intended as a reproducer for #1373.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I1c6b5e072934ba9760cb1f838395e18a4c6bb211