Avoid calling create_wall_timer each new goal, adjust realtime_tools goalhandle accordingly

[ddengster]

https://github.com/ros-controls/ros2_controllers/pull/26 https://github.com/ros-controls/realtime_tools/pull/57

Instead of calling create_wall_timer (which starts a new thread iirc) for each new action goal, runNonRealtime should be decoupled from its object and spinning at action_monitor_rate. And this loop should be able to handle each new goal action goal sent.

[github-actions[bot]]

This issue is being labeled as stale because it has been open 45 days with no activity. It will be automatically closed after another 45 days without follow-ups.

[christophfroehlich]

#428 updated this a bit, but the reported issue still exists.