refactor: Logging (chat logger) (#5058)

It's no longer a singleton

It's now a unique_ptr that dies together with the Application

* Add getChatLogger to EmptyApplication

* unrelated change: Access Application::instance statically

* fix logging init order

* Add changelog entry

src/singletons/Logging.cpp

@@ -12,7 +12,7 @@
 
 namespace chatterino {
 
-void Logging::initialize(Settings &settings, Paths & /*paths*/)
+Logging::Logging(Settings &settings)
 {
     // We can safely ignore this signal connection since settings are only-ever destroyed
     // on application exit

src/singletons/Logging.hpp

@@ -1,6 +1,5 @@
 #pragma once
 
-#include "common/Singleton.hpp"
 #include "util/QStringHash.hpp"
 #include "util/ThreadGuard.hpp"
 
@@ -12,19 +11,15 @@
 
 namespace chatterino {
 
-class Paths;
+class Settings;
 struct Message;
 using MessagePtr = std::shared_ptr<const Message>;
 class LoggingChannel;
 
-class Logging : public Singleton
+class Logging
 {
-    Paths *pathManager = nullptr;
-
 public:
-    Logging() = default;
-
-    void initialize(Settings &settings, Paths &paths) override;
+    Logging(Settings &settings);
 
     void addMessage(const QString &channelName, MessagePtr message,
                     const QString &platformName);