Document load balancer concepts in Reference Architecture

[todkap]

@rbarcia @herness

In discussions about actual production deployments, there is enough interest in how to approach load balancers (external solutions like F5). There is also interest in how to leverage K8 Ingress in conjunction with the ICP Proxy. Can we get these documented in the architecture?

[VictorHavard]

I am working on getting an F5 Load balancer so we can do just this. As soon as I get a license I will create some new docs based on the F5 BIG-IP LTM VE.