Request - Improve array to foreign logic and dictionary viewer

[edsu7]

Summary of request

1. Support element uniqueness check WITHIN array
2. Improve description of array elements mapping to foreign key

Details

As an example I have the following schema:

{
  "name": "my-dictionary",
  "version": "1.0",
  "schemas": [
    {
      "name": "donor",
      "description": "Core donor record",
      "fields": [
        {
          "name": "donor_id",
          "valueType": "string",
          "description": "Unique identifier for the donor",
          "restrictions": {
            "required": true,
            "regex": "^DO-[0-9]{3,}$"
          }
        }
      ],
    "restrictions": {
      "uniqueKey": ["donor_id"]
    }
    },
    {
      "name": "fam",
      "description": "Core donor record",
      "fields": [
        {
          "name": "donor_ids",
          "valueType": "string",
          "isArray": true,
          "delimiter": "|",
          "description": "Unique identifier for the donor",
          "restrictions": {
            "required": true,
            "regex": "^DO-[0-9]{3,}$"
          }
        }
      ],
      "restrictions": {
        "foreignKey": [
          {
            "schema": "donor",
            "mappings": [
              {
                "local": "donor_ids",
                "foreign": "donor_id"
              }
            ]
          }
        ]
      }
    }
  ]
}

Where in fam, multiple donor_ids (in an array) can reference donor_id in donor

1. There's no syntax to check element uniqueness in array.
   e.g. ["A","A","B"]
2. Lectern viewer description could be more descriptive and also references the wrong field:

Desired solution

Re 2.
Example text:

Arrays of `donor_id` as defined in the donor schema. .
Each array element must reference an existing: donor_id in the donor schema. 
Array elements must be unique.

Additional context

Diagram viewer looks good

[joneubank]

Closing this ticket, replaced by #458 and #459