Rename WardenAgentEnvService to FSAgentEnvService

Signed-off-by: Maria Shaldibina <mariash@pivotal.io>
Add RegistryAgentEnvService

To enable registry agent env service the configuration should
contain:

"Actions":{
  "AgentEnvService": "registry",
  "Registry": {
    "Host": "your-registry-host",
    "Port": 1234,
    "Username": "your-registry-user",
    "Password": "your-registry-password"
  }
}

Signed-off-by: Maria Shaldibina <mariash@pivotal.io>
Create WardenFileService

Signed-off-by: Maria Shaldibina <mariash@pivotal.io>
Save metadata when creating VM

Signed-off-by: Maria Shaldibina <mariash@pivotal.io>
Save InstanceID in metadata

Signed-off-by: Maria Shaldibina <mariash@pivotal.io>