Add navigation structure to left-hand side of docs pages

[trentwirth]

Squidfunk uses a different nav structure than we currently do, there is some good design sense in switching over to what he's doing; you can see it here: https://github.com/squidfunk/mkdocs-material/blob/master/mkdocs.yml

So we will! Eventually. :)

[kileyhartigan]

I created a branch off the Troubleshooting branch called Navigation Configuration to address this issue.