Improve how we show the permissions

[dylanratcliffe]

As we add more sources we have to keep updating the permissions in the README.me file. The problem is we also need to update it in lots of other locations:

• In the docs
• In the GUI
• In the S3 bucket that contains the cloudformation template

I think that what we should do instead is have a single source of truth json file that lives in this repo, and then we get it to all the other locations using the following logic:

• The README.md in this repo would just contain a link
• The S3 bucket would be updated as part of the build process, we would put the JSON for the IAM Policy, but also the CloudFormation template
• The GUI would dynamically load the JSON from S3
• The docs dynamically load the JSON from S3