Manage zone records

[BDelacour]

See #196

@ekohl Is it OK for you to manage zone without validation or would you prefer a more specific type (which would lead to a configuration more difficult to maintain) ?

Example :

• I created something like this (in Hiera)

  dns::zones:
  example.com:
  replace_file: true
  serial: 2
  records:
    - host1 IN A 192.168.0.1
    - host2 IN A 192.168.0.2

• Or you want something like this (don't mind the naming, just for the format)

  dns::zones:
  example.com:
  replace_file: true
  serial: 2
  records:
    - name: host1
       xx: IN
       type: A
       dst: 192.168.0.1
  ...