Use AWS ProfileCredentialsProvider on Dev machines.

Dev machines will now pickup credentials from `~/.aws/credentials` see http://blogs.aws.amazon.com/security/post/Tx3D6U6WSFGOK2H/A-New-and-Standardized-Way-to-Manage-Credentials-in-the-AWS-SDKs

At the same time you can now ***run most of the stack without any keys at all*** on a dev machine.

This is broken into 2 categories.

1. Things that will just silently not run when there are no credentials e.g. uploading metrics on dev machines
2. Things that will actively break when there are no credentials e.g. dashboards and some Facia functionality


Good to see this style of endpoint being used, we have lots of aws urls in frontend.