Introduce babeltrace benchmark pipeline

This benchmark pipeline leverage jenkins, lava and
obj.internal.efficios.com.

The babeltrace_benchmark (jobs/babeltrace-benchmark.yaml) jobs is
responsible for queueing lava jobs (
  template_lava_job_bt_benchmark.jinja2 and
  lava/benchmark/babeltrace/benchmark.yml
) and generating the benchmark report graph.

The results for each individual commit lava jobs are uploaded to
obj.internal.efficios.com in the form of a json file.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>