Initial style guide structure

[ipopescu]

As part of this card, start a framework for a style guide:

• have an initial discussion collecting team feedback for the initial structure of a style guide
• add a new page for the initial structure on confluence: https://casperlabs.atlassian.net/wiki/spaces/DEVEXP/overview

The goal of this card is to set a foundation for the style guide. The guide will not be completed in this card but will develop over time, with input from all team members.