Clean up Twitch badge appending code

src/providers/twitch/TwitchBadge.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "messages/MessageElement.hpp"
+
+#include <QString>
+
+namespace chatterino {
+
+class Badge
+{
+public:
+    Badge(QString key, QString value);
+
+    QString key_;           // e.g. bits
+    QString value_;         // e.g. 100
+    QString extraValue_{};  // e.g. 5 (the number of months subscribed)
+    MessageElementFlag flag_{
+        MessageElementFlag::BadgeVanity};  // badge slot it takes up
+};
+
+}  // namespace chatterino