* add metallb auto-assign property for main IP range & update addons.yml for sample inventory
* add new line at the end of file roles\kubernetes-apps\metallb\defaults\main.yml
* set default value for matallb_auto_assign = true
* Option for MetalLB to talk BGP
* Check for BGP peers when metallb_protocol is bgp
* README clarification
* Commented values as documentation only in the sample inventory
* layer 2 or BGP, not both
This changes MetalLB contrib to one of addons for deploying MetalLB with
Kubernetes cluster deployment. By the default, Kubespray doesn't deploy
MetalLB addon.
