Adding User Guide

* Added User Guide section outlines.
* Moved HTTPS example to articles.
* Replaced Hello World example with User Guide.
* Moved use cases out of examples.
* Updated Introduction to add User Guide
* Added Docker.io section
* Added Dockerized section
* Added Using Docker section
* Added Docker Images section
* Added Docker Links section

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)