Allow additional aws parameters like --no-verify-ssl

[stranljip]

I am trying to execute backups in an environment with a self-signed CA which fails because the root ca certificate is not being trusted. It would be helpful if it would be possible to either add a toggle like S3_NO_VERIFY_SSL or even add a parameter like S3_ADDITIONAL_OPTIONS. My specific issue is with the mysql backup but the change would be useful for all images that use the aws client to interact with s3