Add support FrankerFaceZ badges. (#2101)

On startup, we poll https://api.frankerfacez.com/v1/badges/ids and store the mappings of user IDs to badges for the remainder of the applications lifetime.

src/providers/twitch/TwitchMessageBuilder.hpp

@@ -75,6 +75,7 @@ private:
 
     void appendTwitchBadges();
     void appendChatterinoBadges();
+    void appendFfzBadges();
     Outcome tryParseCheermote(const QString &string);
 
     QString roomID_;