Added: `Extras` CF

Added `Extras` CF with a default score of `-10000` to prevent picking up Extras instead of an actual release and to fix #713

docs/json/radarr/extras.json

@@ -0,0 +1,17 @@
+{
+  "trash_id": "0a3f082873eb454bde444150b70253cc",
+  "trash_score": "-10000",
+  "name": "Extras",
+  "includeCustomFormatWhenRenaming": false,
+  "specifications": [
+    {
+      "name": "Extras",
+      "implementation": "ReleaseTitleSpecification",
+      "negate": false,
+      "required": true,
+      "fields": {
+        "value": "(?<=\\b[12]\\d{3}\\b).*\\b(Extras)\\b"
+      }
+    }
+  ]
+}