refactor: Use composition for update time

The timer is not required by all classes and the deep inheritance makes
it hard to see where it is actually used. Use composition instead.

src/misc/worker.h

@@ -299,10 +299,6 @@ namespace swift::misc
         //! \threadsafe
         bool isEnabled() const { return m_enabled; }
 
-        //! Start updating (start/stop timer)
-        //! \threadsafe
-        void startUpdating(int updateTimeSecs);
-
         //! Name of the worker
         const QString &getName() { return m_name; }
 
@@ -323,11 +319,6 @@ namespace swift::misc
         //! Wait time for quitAndWait, 0 means not waiting
         virtual unsigned long waitTimeoutMs() const { return 15 * 1000; }
 
-        //! Safely stop update time
-        void stopUpdateTimer();
-
-        QTimer m_updateTimer { this }; //!< timer which can be used by implementing classes
-
     private:
         //! Called after cleanup().
         void finish();