Added ability to use compaction for multiple devices with similar par…

[mvk15]

Have a server with 12 disks in software raid. Was needed to use 12 stanzas - 1 for every disk for describing disk partitions:

  - device: '/dev/sda'
    partitions:
      - {'num': '1', 'size':  '2M', 'type': 'ef02'}  # /dev/sda1
      - {'num': '2', 'size': '64M', 'type': '8300'}  # /dev/sda2
      - {'num': '3',                'type': '8300'}  # /dev/sda3
    skip_grub: False
  ---%<---- cut ----->%---
  - device: '/dev/sdl'
    partitions:
      - {'num': '1', 'size':  '2M', 'type': 'ef02'}  # /dev/sdl1
      - {'num': '2', 'size': '64M', 'type': '8300'}  # /dev/sdl2
      - {'num': '3',                'type': '8300'}  # /dev/sdl3
    skip_grub: False

After the change is needed only one stanza:

  - device: ['/dev/sda','/dev/sdb','/dev/sdc','/dev/sdd','/dev/sde','/dev/sdf','/dev/sdg','/dev/sdh','/dev/sdi','/dev/sdj','/dev/sdk','/dev/sdl']
    partitions:
      - {'num': '1', 'size':  '2M', 'type': 'ef02'}  # /dev/sd[a-l]1
      - {'num': '2', 'size': '64M', 'type': '8300'}  # /dev/sd[a-l]2
      - {'num': '3',                'type': '8300'}  # /dev/sd[a-l]3
    skip_grub: False

[nilsmeyer]

Very good idea, thank you for the PR.