archive: add --checksum to rsync options

Adding --checksum option to rsync. Rsync compares the creation time on the source and target to ensure a file needs to be synced. We create copies of files we want to archive before running rsync. That means creation times are always different and rsync redundantly syncs over unchanged files. By adding the option, the rsync will compare checksums instead, which should reduce syncing operations.

Helps with TFT-4321