Audit pre-trained list for missing top known trackers

[ghostwords]

Top known trackers according to Ghostery (https://whotracks.me/trackers.html), for instance.

We already know the top missing tracker (#367), but what else should we learn to block but do not at the moment? Once we have candidates, we can start looking into how to tweak the heuristic to catch them. Some of these may already be existing issues (#715, "heuristic" "enhancement" issues in general).

This is a followup to #1891.

[ghostwords]

Google Analytics is blocked by default as of 2019.7.1 (thanks to #2147 and #1947). We should now look into the top (most prevalent) still-undetected-by-Badger trackers.

[ghostwords]

Going by prevalence, Hotjar seems like a good candidate for what to look into next: #715.

[jawz101]

https://github.com/jawz101/TrackersVsFirefox

Lightbeam seems to help me find sites where trackers are found. I trained on just 25 sites and some of them show good examples

scripts for analytics.twitter.com and static.ads-twitter.com can be found on latimes.com. OpenX is pretty much everywhere but they use a lot of different subdomains

  "us-u.openx.net": {
    "hostname": "us-u.openx.net",
    "favicon": "",
    "firstPartyHostnames": [
      "www.latimes.com",
      "www.nytimes.com",
      "www.merriam-webster.com",
      "www.theguardian.com",
      "www.tomshardware.com",
      "www.cnet.com",
      "www.chicagotribune.com",
      "www.cnn.com",
      "www.usatoday.com",
      "lifehacker.com",
      "weather.com",
      "www.tmz.com",
      "www.aol.com",
      "www.snopes.com",
      "www.avsforum.com",
      "www.androidpolice.com"