s3: add support for KMS Key ID - fixes #2217
s3: add support for KMS Key ID - fixes #2217

This code supports aws:kms and the kms key id for the s3 backend.
B4dM4n/rclone,ncw/rclone,ncw/rclone,B4dM4n/rclone,ncw/rclone,olihey/rclone,ncw/rclone,B4dM4n/rclone,B4dM4n/rclone,olihey/rclone,olihey/rclone,olihey/rclone