Implement hyper_v::instance type

[luisfdez]

@ppouliot, I'm opening this issue to track the details of the new custom type we commented yesterday.

My first idea is somehing like:

hyperv_instance { 'Dev Instance':
  ensure          => present,                 # 'present' / 'absent'
  name            => 'dev_instance', 
  ram             => 512,                     # MB
  disk_size       => 10240,                   # MB
  disk_path       => 'C:\Instances\disk.vhd', # Detect if it exists or not and create it
  mac             => '00:00:00:00:00:00',     # if not specified, random.
  automatic_start => always,                  # 'always', 'if_running', 'nothing'
  automatic_stop  => save,                    # 'save', 'turnoff', 'shutdown'
  require         => Class['hyper_v'],
}

Future improvements could be types like:

hyperv_network_adapter { 'internal adapter':
  switch   => 'private_switch',
  instance => 'dev_instance',
  vlan_id  => 3,
  mac      => '01:02:03:04:05:06'
  require  => [Hyperv_instance['Dev instance'], Virtual_switch['private_switch']],
}