src.ctf.lttng-live: use the new metadata stream parser and message iterator

src.ctf.lttng-live: use the new metadata stream parser and message iterator

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Id2e11205bed54654942077c5336495b7bdd3f38d
Reviewed-on: https://review.lttng.org/c/babeltrace/+/8617
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/8648