Change backup compression program from bzip2 to xz
Change backup compression program from bzip2 to xz

Backup size is growing rapidly and downloading of backups starts
to take even longer. Therefore changing to xz for compression.
A tradeoff here is a considerably longer compression time.

terop/env-logger,terop/env-logger,terop/env-logger,terop/env-logger,terop/env-logger,terop/env-logger,terop/env-logger