ApiDocument index data can now also be already analyzed data

example:
{
    "uri": "ex://21",
    "description": { "content" : "Auge um Auge" },
    "index": {
      "who": {
        "Auge": [0,2],
        "um": [1]
      }
    }
}

or

{
    "uri": "ex://21",
    "description": { "content" : "Auge um Auge" },
    "index": {
      "who": {
        "content" : "Auge um Auge"
      }
    }
}
Remove IndexData wrapper and use Either

Uses FromJSON/ToJSON instances for (Either WordList TextData)
Cleanup