Reduce threshold of the node-exporter alert to 15% space available, instead of 20% (default).

As per https://github.com/coreos/kube-prometheus/issues/294



Signed-off-by: iuri aranda <iuri@skyscrapers.eu>

Includes prometheus-operator v0.35.1 which should fix the statefulset
crash loop issue #2950

This prevents mismatch between prometheus-operator binary and related
CRD yaml files.

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

Signed-off-by: Benjamin <benjamin@yunify.com>

Upgrade to prometheus/node_exporter@d574b4b, which includes a better
metric for memory saturation.

See prometheus/node_exporter#1524.

Pick up new alerts for unreachable nodes.

* Bumping prometheus-adapter and Grafana versions

* Bumping prometheus-adapter version in libsonnet file

* Regenerating lockfile

* Bumping Grafana version in libsonnet file

* Updating kustomization.yaml