This adds a Sonobuoy chart that only runs the systemd-logs plugin[1]. The
Sonobuoy pod (tests) are executed as a `helm test`.
This chart must be installed under the heptio-sonobuoy namespace[2]. A node
with the label selector specified in values.yaml (labels.api) must exist
for the Sonobuoy pod to even be created.
Also add an experimental job to test Sonobuoy chart.
[1] https://github.com/heptio/sonobuoy-plugin-systemd-logs
[2] https://github.com/heptio/sonobuoy/issues/420
Change-Id: I613fab635b97a70ac20820e1ececde48952ac2da
f823544adb