* Adds support for Multus (multiple interfaces) CNI plugin

Multus is a latin word for "Multi". As the name suggests, it acts as a
Multi plugin in Kubernetes and provides multiple network interface
support in a pod. Multus uses the concept of invoking delegates by
grouping multiple plugins into delegates and invoking them in the
sequential order of the CNI configuration file provided in json format.

* Change CNI version (0.1.0->0.3.1) of Contiv to be compatible with Multus

Upstream Changes:

   - coredns v1.2.5 (https://github.com/coredns/coredns/releases/tag/v1.2.5)

NOTE:

   - Switch image repo to https://hub.docker.com/r/coredns/coredns/ (https://github.com/kubernetes-incubator/kubespray/pull/3595#issuecomment-433962973)

This reverts commit 8ba6b601.

Upstream Changes:

-   ingress-nginx 0.20.0 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.20.0)

Our Changes:

-   Sync templates with upstream changes

* failed

* version_compare

* succeeded

* skipped

* success

* version_compare becomes version since ansible 2.5

* ansible minimal version updated in doc and spec

* last version_compare

* [jjo] add kube-router support

Fixes cloudnativelabs/kube-router#147.

* add kube-router as another network_plugin choice
* support most used kube-router flags via
  `kube_router_foo` vars as other plugins
* implement replacing kube-proxy (--run-service-proxy=true) via
  `kube_proxy_mode: none`, verified in a _non kubeadm_enabled_
  install, should also work for recent kubeadm releases via
  `skipKubeProxyInstall: true` config

* [jjo] address PR#3339 review from @woopstar

* add busybox image used by kube-router to downloads

* fix busybox download groups key

* rework kubeadm_enabled + kube_router_run_service_proxy

- verify it working ok w/the kubeadm_enabled and
  kube_router_run_service_proxy true or false

- introduce `kube_proxy_remove` fact, to decouple logic
  from kube_proxy_mode (which affects kubeadm configmap
  settings, thus no-good to ab-use it to 'none')

* improve kube-router.md re: kubeadm_enabled and kube_router_run_service_proxy

* address @woopstar latest review

* add inventory/sample/group_vars/k8s-cluster/k8s-net-kube-router.yml

* fix kube_router_run_service_proxy conditional for kube-proxy removal

* fix kube_proxy_remove fact (w/ |bool), add some needed kube-proxy tags on my and existing changes

* update kube-router tolerations for 1.12 compatibility

* add PriorityClass to kube-router DaemonSet

* Specify that the cluster.yml playbook should run as root

This is a possible fix for #3388.
The following examples show the option `-b` too:

https://kubernetes.io/docs/setup/custom-cloud/kubespray/
https://github.com/kubernetes-incubator/kubespray/blob/master/docs/getting-started.md#starting-custom-deployment

* Update invocation to include specific root user

* Update comment text according to suggestions

https://github.com/kubernetes/kubernetes/issues/69214

* Upgrade kubernetes to v1.12.0

Use kubeadm v1alpha3 config

* Upgrade coredns and etcd

* Upgrage docker to 18.06

Internet access is not mandatory as long as the user configures all container image repositories to point to internal container registries, in case of on-premises installation with firewall rules preventing direct Internet access.

Upstream Changes:

-   weave 2.4.1 (https://github.com/weaveworks/weave/releases/tag/v2.4.1)

Our Changes:

-   Templates sync with upstream manifests

Upstream Changes:

-   cert-manager 0.5.0 (https://github.com/jetstack/cert-manager/releases/tag/v0.5.0)

Our Changes:

-   Templates sync with upstream manifests

It wan't obvious for me how to join this channel.

Upstream Changes:

-   ingress-nginx 0.19.0 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.19.0)

Our Changes:

-   Sync templates with upstream changes

Upstream Changes:

-   cephfs-provisioner v2.1.0-k8s1.11 (https://github.com/kubernetes-incubator/external-storage/releases/tag/cephfs-provisioner-v2.1.0-k8s1.11)

Our Changes:

-   Sync clusterrole and role with upstream changes

Upstream Changes:

-   coredns v1.2.2 (https://github.com/coredns/coredns/releases/tag/v1.2.2)

NOTE:

-   coredns image for 1.2.0 and 1.2.1 had been removed from https://console.cloud.google.com/gcr/images/google-containers/GLOBAL/coredns

* calico upgrade to v3

* update calico_rr version

* add missing file

* change contents of main.yml as it was left old version

* enable network policy by default

* remove unneeded task

* Fix kubelet calico settings

* fix when statement

* switch back to node-kubeconfig.yaml

Signed-off-by: Jeff Bornemann <jeff.bornemann@oracle.com>

Upstream Changes:

-   cephfs-provisioner v2.0.0-k8s1.11 (https://github.com/kubernetes-incubator/external-storage/releases/tag/cephfs-provisioner-v2.0.0-k8s1.11)
-   Update ClusterRole

Our Changes:

-   Fix typo in defaults/main.yml (rs -> deploy)
-   Manifests cleanup

Upstream Changes:

-   cert-manager 0.4.1 (https://github.com/jetstack/cert-manager/releases/tag/v0.4.1)

Our Changes:

-   Better templates sync with upstream manifests
-   Remove fancy resources requests/limits customization

Upstream Changes:

-   ingress-nginx 0.18.0 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.18.0)

Upgrade Kubernetes to V1.11.2
The kubeadm configuration file version has been upgraded from v1alpha1 to v1alpha2
Add bootstrap kubeadm-config.yaml with external etcd