Hybrid projects

# Including CSS best practices for Hybrid App projects

Status: **Up For Review**

Reviewers: @kpeatt @rosshojo @jeffkamo @mobifydave @jansepar 
JIRA: https://mobify.atlassian.net/browse/GOLD-1164

## Changes
- Initialized new page in the css code styles and filled in what we currently have established as best practices.
I'm not @shawn, that random lucky person with a great name will randomly be added to this convo :)

So, let's talk performance here for a second. Looking at what we have today in the BTR app, we have 9 new files introduced. Looking at these files, they are actually quite small. I'm pretty sure if we added them up and minified them, it would be under 1KB. This actually makes sense considering the differences between the smartphone and app (style wise) are quite minimal.

A 1KB difference will *barely* make a difference in load times, so I'm not convinced that it's worth the added complexity. For me right now, I feel like the only reason it would make sense to have a separate file is if it reduced complexity.

I'd also like to bring up my previous point regarding the fact that in responsive sites, you don't have different CSS for different platforms. Again, if we're not splitting things up for performance sake by having separate files on desktop vs mobile, then why would we do things differently for apps? What makes the app vs web argument any different from the desktop vs mobile argument?