s3: add GLACIER storage class
s3: add GLACIER storage class

Fixes #923
olihey/rclone,B4dM4n/rclone,B4dM4n/rclone,B4dM4n/rclone,B4dM4n/rclone,ncw/rclone,ncw/rclone,olihey/rclone,ncw/rclone,olihey/rclone,ncw/rclone,olihey/rclone