rename `babeltrace.trace-info` to `babeltrace.trace-infos`, `streams` to `stream...

rename `babeltrace.trace-info` to `babeltrace.trace-infos`, `streams` to `stream-infos`

Because the query response is a list of potentially multiple trace
infos, use the plural form for the object name.

Change-Id: I6b742b4993d1a1552c1d189c54759821d4fd069c
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/1999
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Francis Deslauriers <francis.deslauriers@efficios.com>