Make TwitchEmotes class conform to QString standard

Make twitch emotes only be identified by a string ID, instead of sometimes by a string and sometimes by an int

Make the EmoteSet a struct instead of just a vector of emotes. This will be handy when we later fill in the emote sets name and other info (i.e. whether it's a subscription benifit or not)

src/providers/twitch/twitchmessagebuilder.cpp

@@ -498,7 +498,7 @@ void TwitchMessageBuilder::appendTwitchEmote(const Communi::IrcMessage *ircMessa
         return;
     }
 
-    long int id = std::stol(parameters.at(0).toStdString(), nullptr, 10);
+    const auto &id = parameters.at(0);
 
     QStringList occurences = parameters.at(1).split(',');