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/util/Helpers.hpp

@@ -1,16 +1,9 @@
 #pragma once
 
-#include <fmt/format.h>
 #include <QString>
 
 namespace chatterino {
 
-template <typename... Args>
-auto fS(Args &&... args)
-{
-    return fmt::format(std::forward<Args>(args)...);
-}
-
 QString generateUuid();
 
 QString formatRichLink(const QString &url, bool file = false);
@@ -21,13 +14,3 @@ QString formatRichNamedLink(const QString &url, const QString &name,
 QString shortenString(const QString &str, unsigned maxWidth = 50);
 
 }  // namespace chatterino
-
-namespace fmt {
-
-// format_arg for QString
-inline void format_arg(BasicFormatter<char> &f, const char *&, const QString &v)
-{
-    f.writer().write("{}", v.toStdString());
-}
-
-}  // namespace fmt