Fixes #455.

Grafana deployment needs to modified for weave-net for mounting the
weave-net config maps volumes

https://github.com/coreos/kube-prometheus/pull/425#pullrequestreview-368779890

Review comment: https://github.com/coreos/kube-prometheus/pull/425#discussion_r387494885

Propose in this https://github.com/brancz/kubernetes-grafana/pull/78

* Avoid race condition when deploying quickstart example

The namespace and CRD creation must happen before any dependent objects
are created.  So we can put these in a separate directory (manifest/setup)
so they can be created before the other objects.

Some minor updates to the README and added a couple of scripts
for the quickstarts

Update travis script to avoid race condition

Signed-off-by: Paul Gier <pgier@redhat.com>

* simplify the example quickstart script and improve readme

Signed-off-by: Paul Gier <pgier@redhat.com>

* increase minikube memory to 6g for quickstart example

From the discussion brought up in this [issue](https://github.com/coreos/prometheus-operator/issues/2250), a new section has been added to the doc.

the operator spec key is named "externalUrl", rather than "externalURL"

Explicitly reference values we are interesting in (jsonnet style)
instead of just following conventions (helm style)

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

Resolves issue #1629 in this repository.

replaced default namespaces rbac rules by a loop


set right variable name