Sync bootstrap scripts from Akraino IEC wiki

Bring in sh scripts from IEC Wiki page [1]:

The initial setup scripts to be executed on all cluster nodes:
- k8s_common:
  * prerequisites;
  * Kubernetes Install for Ubuntu, using Kubeadm;

The following scripts should be executed on K8s master node:
- k8s_master:
  * setup host as K8s master;
- calico:
  * setup etcd, RBAC roles, calico;
- nginx:
  * verify basic K8s functionality;
- helm:
  * bring in `tiller` and `helm` binaries;

There is one more step that is not covered by the current scripts:
- K8s slave nodes should execute `kubeadm join` after the k8s_master
  script has completed;

[1] https://wiki.akraino.org/display/AK/\
    IEC+Blueprints+Installation+Overview

Change-Id: I8d4f78b7482486e2c4a31db35cddb0c1570307a5
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>