add script to upload/download pip cache directories from S3

Add in one level of folders, for the version of this script. This one will be "v1". 
That way we can set up the bucket permissions, etc. knowing that if we want to invalidate all caches created already we will only need to select the entire folder for deletion instead of every file created.
This will also future-proof us in case we want to change the naming scheme later, etc.