Move file storage into S3

[arowla]

Move file storage to S3 for:

-[ ] fbo
-[ ] grants
-[ ] bids.state.gov

This work also needs to be done for the attachment loaders, so make sure you coordinate on how it's done (#183).

[arowla]

There should be an S3 broker available in cloud.gov now. Ask one of the devops folks if you don't see it when you run cf marketplace in the fbopen org. They can enable it.

The files in S3 should be set to expire after a reasonable time period for debugging has passed, like a week or two.