Add a PathManager that takes care of all paths and creating folders

Move all path/folder-related code from SettingManager to PathManager

src/singletons/pathmanager.hpp

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <QString>
+
+namespace chatterino {
+namespace singletons {
+
+class PathManager
+{
+    PathManager() = default;
+
+public:
+    static PathManager &getInstance();
+
+    bool init(int argc, char **argv);
+
+    QString settingsFolderPath;
+    QString customFolderPath;
+};
+
+}  // namespace singletons
+}  // namespace chatterino