@dblock: new post: "Introduction to AWS OpsWorks"

I decided to split this into an introduction and then a follow-up that documents some of our specific extensions and lessons. This is the first part.

Thanks to @mzikherman and @fancyremarker for comments.

You can see a somewhat better-formatted view of the article [here](https://github.com/joeyAghion/artsy.github.com/blob/9dd1c15fc9b618a9976fbbe2e823d3d2fe272b6b/source/_posts/2013-08-27-introduction-to-aws-opsworks.markdown) (sans images).

I'll take care of the post-merge deploy.