uploader feeds surrogate key to s3uploader
uploader feeds surrogate key to s3uploader

The surrogate key comes from the JSON response when registering a build
with LTD Keeper.

Also, explicitly pass the public-read ACL and Cache-Control values needed
for this S3+Fastly-based publishing setup.

lsst-sqre/ltd-mason,lsst-sqre/ltd-mason