Implementation of "migration manager" to fix placement of config files issue appeared after moving from Qt 5 to Qt 6

client/migrations.h

@@ -0,0 +1,24 @@
+#ifndef MIGRATIONS_H
+#define MIGRATIONS_H
+
+#include <QObject>
+
+class Migrations : public QObject
+{
+    Q_OBJECT
+public:
+    explicit Migrations(QObject *parent = nullptr);
+
+    void doMigrations();
+
+private:
+    void migrateV3();
+
+private:
+    int currentMajor = 0;
+    int currentMinor = 0;
+    int currentMicro = 0;
+    int currentPatch = 0;
+};
+
+#endif // MIGRATIONS_H