Add support for Mixer streaming service

data.json

@@ -1194,5 +1194,13 @@
     "urlMain": "https://last.fm/",
     "username_claimed": "blue",
     "username_unclaimed": "noonewouldeverusethis7"
+  },
+  "mixer.com":
+  {
+    "errorType": "status_code",
+    "url": "https://mixer.com/{}",
+    "urlMain": "https://mixer.com/",
+    "username_claimed": "blue",
+    "username_unclaimed": "noonewouldeverusethis7"
   }
 }