objects: improve support for our s3 deployment
Not sure how well this generalizes but we can improve it when someone
complains.
Switch from minio to AWS SDK S3 client
Moves s3 => objects to avoid conflicting with the AWS module.
all: pass errors to panic, not strings
GraphQL's recovery middleware can't handle strings so it just logs a
very not useful <nil>
s3: add [objects]s3-insecure
Disables TLS. Useful for local development.
s3: add NewClient and URL
Centralizes the logic to create an S3 client and get the base URL.