JSON:API - Optimize facet output

[ewlarson]

Our current facet implementation duplicates a lot of "text", with labels and values and so many links.

    "type": "facet",
      "id": "dct_language_sm",
      "attributes": {
        "label": "Dct Language",
        "items": [
          {
            "attributes": {
              "label": "English",
              "value": "English",
              "hits": 5970
            },
            "links": {
              "self": "https://lib-btaageoapi-dev-app-01.oit.umn.edu/api/v1/search?q=&include_filters%5Bdct_language_sm%5D%5B%5D=English"
            }
          },

We could optimize the facet response to something like:

"items": [["Wisconsin",13648], ["Indiana",12693], ...]

And! Perhaps we even skip the link generation — leaving that for the client logic to implement??