FlightOrder deviceType and documentType

[steve-donovan]

Description

FlightOrder currently defines deviceType and documentType as String, they should really be enums for friendlier API

I noticed someone in discord with the issue.

as per spec

    "PhoneDeviceType": {
      "type": "string",
      "description": "Type of the device (Landline, Mobile or Fax)",
      "enum": [
        "MOBILE",
        "LANDLINE",
        "FAX"
      ]
    },

        "DocumentType": {
      "type": "string",
      "description": "the nature/type of the document",
      "enum": [
        "VISA",
        "PASSPORT",
        "IDENTITY_CARD",
        "KNOWN_TRAVELER",
        "REDRESS"
      ],
      "example": "VISA"
    },