Configurable token auth for media bucket filters

[jdspugh]

If I call a media bucket with a filter query like /media/mediaStore?filter={"status":"todo"} it seems it always needs to be authenticated. There should be a configuration setting to turn it off on a per bucket basis like we can with collection endpoints. I recommend a setting like this in config.development/production.json files:

 "media" : {
    "mediaStore": {
      "authenticate": <true|false>
    }
  },