test(backup): add native/rclone backup benchmarking under read/write stress

[kreuzerkrieg]

RW latency during backup using rclone/native

Test requirements See here

Argus run https://argus.scylladb.com/tests/scylla-cluster-tests/27b9e340-c851-4e74-ba37-d55e28efd8e0

	Size	Time [s]
rclone based backup	2.962TiB	04:28:52
rclone based restore	17.766TiB	06:27:55
rclone based backup during R/W stress	2.942TiB	04:02:09

	read time [s]	op rate [op/s]	partition rate [pk/s]	row rate [row/s]	latency 99th percentile [ms]
Read stress: with concurrent rclone based backup	01:00:38	86108.50	86108.50	86108.50	3.41
Write stress: with concurrent rclone based backup	01:00:38	99487.50	99487.50	99487.50	3.17
Read stress: w/o concurrent backup	01:00:37	84699.25	84699.25	84699.25	3.61
Write stress: w/o concurrent backup	01:00:37	99051.00	99051.00	99051.00	3.44

fixes: https://github.com/scylladb/scylla-cluster-tests/issues/8752

cc: @regevran