Install Rancher Server with TK8 as addon and provide additional how-to

[arashkaffamanesh]

tk8 addon --rancher
should install this manifest:
https://raw.githubusercontent.com/arashkaffamanesh/tk8/master/rancher/rancher.yaml

And we need to provide an how-to about exposing the rancher server via ingress / loadbalancer and write a blog post on medium.

and the help should be extended:

Flags:
-m, --heapster Deploy Heapster
-h, --help help for addon
-l, --ltaas Deploy Load Testing As A Service
-p, --prom Deploy prometheus
-r, --rancher Deploy Rancher Server