Split apart the "display" property

[JaceHensley]

So currently the "display" property is used before and after the holder has a credential. I think this should be split apart to two separate properties, for before and after the holder recieves a credential.

{
  "output_descriptors": [
    {
      // ...
      "offer_display": {
        "title": {
          "text": "Washington State Driver License"
        },
        "subtitle": {
          "text": "Class A, Commercial"
        },
        "description": {
          "text": "License to operate a vehicle with a gross combined weight rating (GCWR) of 26,001 or more pounds, as long as the GVWR of the vehicle(s) being towed is over 10,000 pounds."
        },
        "properties": [
          {
            "label": "Organ Donor",
            "text": "True/False"
          }
        ]
      },
      "display": {
        "title": {
          "path": ["$.name", "$.vc.name"],
        },
        "subtitle": {
          "path": ["$.class", "$.vc.class"],
        },
        "properties": [
          {
            "path": ["$.donor", "$.vc.donor"],
            "label": "Organ Donor"
          }
        ]
      }
    }
  ]
}

This "offer_display" (I don't like this name, open to others!) would be used to show the holder info about the credential before they submit the "presentation_submission" and would hold static "text" fields. And then the "display" property is strictly drived from the credential (using "path" to find the field to display from the credential).

---

There was also some talk on whether the current "display" object should be embedded into the issued credential. If we want to do that then I'd suggest keeping "offer_display" (just "text" and "label" + "text") on the Output Descriptor but keep the name "display".

{
  "output_descriptors": [
    {
      // ...
      "display": {
        "title": {
          "text": "Washington State Driver License"
        },
        "subtitle": {
          "text": "Class A, Commercial"
        },
        "description": {
          "text": "License to operate a vehicle with a gross combined weight rating (GCWR) of 26,001 or more pounds, as long as the GVWR of the vehicle(s) being towed is over 10,000 pounds."
        },
        "properties": [
          {
            "label": "Organ Donor",
            "text": "True/False"
          }
        ]
      },
    }
  ]
}

{
  "type": ["VerifiableCredential", "..."],
  "display": {
    "title": {
      "path": ["$.name", "$.vc.name"],
    },
    "subtitle": {
      "path": ["$.class", "$.vc.class"],
    },
    "properties": [
      {
        "path": ["$.donor", "$.vc.donor"],
        "label": "Organ Donor"
      }
    ]
  }
  // ...
}

[JaceHensley]

Explained better in #44