Moved to XFS

This is the latest edition of my current backup program benchmark.

• I've moved from ZFS to XFS for the linux kernel source remote backup benchmarks in order to have comparable file size results
• Improved feature comparaison table
• Newer backup program versions

New backend support

In this test series, http backend support has been added for restic and kopia.
Also, restic team released 0.14.0 including compression, so restic_beta test has been dropped.

Initial tests

This is the first release of backup-bench.sh, including test results.