Add section on Reverse Proxy in Cookbook/CONCEPTS
Add section on Reverse Proxy in Cookbook/CONCEPTS

Add a section about Reverse Proxies, to explain what they are, why
you should care about them and how to solve the problem they introduce.

s1037989/mojo,marcusramberg/mojo,dotandimet/mojo,kraih/mojo,jamadam/mojo,Grinnz/mojo,s1037989/mojo,lindleyw/mojo,kberov/mojo,polettix/mojo,kiwiroy/mojo,CandyAngel/mojo