Use S3 URLs rather than proxying

Instead of proxying the data from S3 we can probably improve cost and performance by generating an expiring link to download the resources from S3 instead.

I am envisioning that it is just an option to tick off rather than a redo of the blob store.  It should provide a warning stating that the resources MAY be exposed to the outside as the links being generated are public links even if they expire.

It should have a couple of options to specify the expiration period and a minimum expiration period remaining before to request a new token.