Merge pull request 'Added isRunning to timer' (#6) from timer-isRunning into main

Reviewed-on: https://git.intern.spaceteamaachen.de/ALPAKA/sta-core/pulls/6
Reviewed-by: carlwachter <carlwachter@noreply.git.intern.spaceteamaachen.de>

include/sta/timer.hpp

@@ -27,6 +27,13 @@ namespace sta
          *
          */
         virtual void stop() = 0;
+        /**
+         * @brief Check if timer is running.
+         *
+         * @return true if timer is running
+         * @return false if timer is not running
+         */
+        virtual bool isRunning() = 0;
     };
 } // namespace sta