Documentation for S3 config, example guide image uploader


# What's New?

 * Documented the process of how S3 authentication will work
 * Built a fake Guide creation form within `/pages/test` for @simonv3 and co. to take a look at as an example.
 * Split permissions into a serverside S3 policy and a clientside S3 policy.

# What's Next?

 * Build a better directive for file uploads or fork NGS3Upload
 * Fix test suite.