ci: use /dev/disk/by-id

ci: use /dev/disk/by-id

Due to parallel probing of the linux kernel `/dev/sd*` can't be used to
reliably address a hard disk. This can be seen by the many spurious
failures of the dracut CI, where `mdadm` failed with error 524 or tests
failed due to the success marker message written to the wrong disk.

* don't rely on `/dev/sd*` but use disk ids and `/dev/disk/by-id/ata-disk_<name>`

* specify the exact qemu machine architecture `-M q35` needed for the
  disk ids. A later patch will move this to `run-qemu`, when all tests are converted

* due to `-M q35` the interface names have changed from
  `ens2` -> `enp0s1` and `ens3` -> `enp0s2`