Porting Marathon Networking Doc to DC/OS

[sascala]

Description

@jdef I'm assigning this to you because it's related to the Marathon networking doc you authored. I'm porting it over to the DC/OS site and I have some related questions. I also moved some information from the examples section up into the reference section because it seemed pretty important.

Urgency

• [ ] Blocker
• [ ] High
• [ ] Medium

Requirements

• Test all commands and procedures.
• Build content locally and test for formatting/links.
• Add redirects to dcos-website/redirect-files.
• Change all affected versions (e.g. 1.7, 1.8, and 1.9).
• See the contribution guidelines.

[sascala]

@pavisandhu This is a work in progress. We need to incorporate the marathon networking doc into the dc/os site however you think it's best.