This commit adjusts the RBAC proxy for the node-exporter DaemonSet to
only listen on the Pod IP. It also adjusts the ports used by the
node-exporter Pod so that both containers are listening on 9100. The
actual node-exporter listens on 127.0.0.1:9100, while the RBAC proxy
listens on <PODIP>:9100. This ensures that port 9101 is not taken on
the host networking namespace.

kube-prometheus: Add documentaton to README on the Pod Anti-Affinity mixin

Update alertmanager retention documentation

contrib/kube-prometheus: Update experimental Custom Metrics adapter example

Currently there is no documentation on the Pod Anti-Affinity mixin which makes it
difficult to find. To address this, this PR adds a section to the README on how one
can use it.

Use interval in ServiceMonitor endpoint

Reintroduce updated dpeloy.sh & teardown.sh

contrib/kube-prometheus: Add section on Prometheus Adapter requirements to README.md

kube-prometheus: Example jsonnet ingress, add externalURL