Remove FMT dependency (#1472)

All occurrences of log() have been replaced with qDebug()

bonus meme: remove a bunch of std::string usages in the pubsub client

Fixes #1467

src/providers/twitch/TwitchHelpers.cpp

@@ -1,5 +1,4 @@
 #include "providers/twitch/TwitchHelpers.hpp"
-#include "debug/Log.hpp"
 
 namespace chatterino {
 
@@ -7,7 +6,7 @@ bool trimChannelName(const QString &channelName, QString &outChannelName)
 {
     if (channelName.length() < 2)
     {
-        log("channel name length below 2");
+        qDebug() << "channel name length below 2";
         return false;
     }