Create a contribution guide with our general coding standards

[Cooperbuilt]

Goal

We currently have no contribution guide for folks. We should have a contribution guide with the following:

1. Outline of our SCSS SUIT standards
2. Outline of our general testing best practices
3. Code of conduct
   ....anything else folks can think about.

People

I am going to tag this to the repo maintainers.
In my opinion, we should port over the styles we abide by to this repo.
@SheaBelsky @rellison192 @helloitsjoe