task/internal/syslog: parallelize and debugify gzip of syslogs

task/internal/syslog: parallelize and debugify gzip of syslogs

To match what we do for the ceph task.

Looks like:

    2025-07-21T17:04:25.354 INFO:teuthology.task.internal.syslog:Compressing syslogs...
    2025-07-21T17:04:25.354 DEBUG:teuthology.orchestra.run.smithi117:> find /home/ubuntu/cephtest/archive/syslog -name '*.log' -print0 | sudo xargs -0 --max-args=1 --max-procs=0 --verbose --no-run-if-empty -- gzip -5 --verbose --
    2025-07-21T17:04:25.357 DEBUG:teuthology.orchestra.run.smithi142:> find /home/ubuntu/cephtest/archive/syslog -name '*.log' -print0 | sudo xargs -0 --max-args=1 --max-procs=0 --verbose --no-run-if-empty -- gzip -5 --verbose --
    2025-07-21T17:04:25.359 DEBUG:teuthology.orchestra.run.smithi186:> find /home/ubuntu/cephtest/archive/syslog -name '*.log' -print0 | sudo xargs -0 --max-args=1 --max-procs=0 --verbose --no-run-if-empty -- gzip -5 --verbose --
    2025-07-21T17:04:25.380 INFO:teuthology.orchestra.run.smithi117.stderr:gzip -5 --verbose -- /home/ubuntu/cephtest/archive/syslog/misc.log
    2025-07-21T17:04:25.380 INFO:teuthology.orchestra.run.smithi117.stderr:gzip -5 --verbose -- /home/ubuntu/cephtest/archive/syslog/kern.log
    2025-07-21T17:04:25.380 INFO:teuthology.orchestra.run.smithi117.stderr:/home/ubuntu/cephtest/archive/syslog/misc.log:   gzip -5 --verbose -- /home/ubuntu/cephtest/archive/syslog/journalctl.log
    2025-07-21T17:04:25.381 INFO:teuthology.orchestra.run.smithi117.stderr:  0.0% -- replaced with /home/ubuntu/cephtest/archive/syslog/misc.log.gz
    2025-07-21T17:04:25.381 INFO:teuthology.orchestra.run.smithi117.stderr:/home/ubuntu/cephtest/archive/syslog/kern.log:     0.0% -- replaced with /home/ubuntu/cephtest/archive/syslog/kern.log.gz
    2025-07-21T17:04:25.385 INFO:teuthology.orchestra.run.smithi142.stderr:gzip -5 --verbose -- /home/ubuntu/cephtest/archive/syslog/misc.log
    2025-07-21T17:04:25.385 INFO:teuthology.orchestra.run.smithi142.stderr:gzip -5 --verbose -- /home/ubuntu/cephtest/archive/syslog/kern.log
    2025-07-21T17:04:25.385 INFO:teuthology.orchestra.run.smithi142.stderr:/home/ubuntu/cephtest/archive/syslog/misc.log:   gzip -5 --verbose -- /home/ubuntu/cephtest/archive/syslog/journalctl.log
    2025-07-21T17:04:25.385 INFO:teuthology.orchestra.run.smithi142.stderr:  0.0% -- replaced with /home/ubuntu/cephtest/archive/syslog/misc.log.gz
    2025-07-21T17:04:25.385 INFO:teuthology.orchestra.run.smithi142.stderr:/home/ubuntu/cephtest/archive/syslog/kern.log:     0.0% -- replaced with /home/ubuntu/cephtest/archive/syslog/kern.log.gz
    2025-07-21T17:04:25.386 INFO:teuthology.orchestra.run.smithi186.stderr:gzip -5 --verbose -- /home/ubuntu/cephtest/archive/syslog/misc.log
    2025-07-21T17:04:25.387 INFO:teuthology.orchestra.run.smithi186.stderr:gzip -5 --verbose -- /home/ubuntu/cephtest/archive/syslog/kern.log
    2025-07-21T17:04:25.387 INFO:teuthology.orchestra.run.smithi186.stderr:gzip -5 --verbose -- /home/ubuntu/cephtest/archive/syslog/journalctl.log
    2025-07-21T17:04:25.387 INFO:teuthology.orchestra.run.smithi186.stderr:/home/ubuntu/cephtest/archive/syslog/misc.log:     0.0% -- replaced with /home/ubuntu/cephtest/archive/syslog/misc.log.gz
    2025-07-21T17:04:25.387 INFO:teuthology.orchestra.run.smithi186.stderr:/home/ubuntu/cephtest/archive/syslog/kern.log:     0.0% -- replaced with /home/ubuntu/cephtest/archive/syslog/kern.log.gz
    2025-07-21T17:04:25.423 INFO:teuthology.orchestra.run.smithi142.stderr:/home/ubuntu/cephtest/archive/syslog/journalctl.log:      88.4% -- replaced with /home/ubuntu/cephtest/archive/syslog/journalctl.log.gz
    2025-07-21T17:04:25.426 INFO:teuthology.orchestra.run.smithi186.stderr:/home/ubuntu/cephtest/archive/syslog/journalctl.log:      88.5% -- replaced with /home/ubuntu/cephtest/archive/syslog/journalctl.log.gz
    2025-07-21T17:04:25.502 INFO:teuthology.orchestra.run.smithi117.stderr:/home/ubuntu/cephtest/archive/syslog/journalctl.log:      90.5% -- replaced with /home/ubuntu/cephtest/archive/syslog/journalctl.log.gz

Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>