Refactor fabric|subnet|vlan|ranges

  * return human-readable error in multiply plases
    by default - just return 400
  * fix passing 'primary_rack' into update_vlan command
    maas_name != rack_controller name
    And even more:
        type primary_rack system_id != system name!
    But,disabling thise - since not work in '2.3.3-6498-ge4db91d'
  * fix vlan
    VID != VLAN. Even if this logic partially broken in maas
  * Fabrics:
    fix ordering, since in case of creating subnet with VLAN
    - create fabric
    - create subnet with ranges and vid
    - update fabric to provide DHCP
  * ipranges: remove unneeded 'multiple' behaviour

Closes-Bug: PROD-21123 (PROD:21123)

Change-Id: I24c946882cdaf6d92e38d0ce79576a830fe1978f
4 files changed