* adds a work_queue systemcmd that will bring a tree view of all active work queues and work items
* WorkQueues now track attached WorkItems and will shutdown when the last WorkItem is detached
This new airspeed module does:
-runns an airspeed validator for every airspeed sensor present, which checks measurement validity and estimates an airspeed scale
-selects another airspeed sensor if for the current one a failure is detected
-estimates airspeed with groundspeed-windspeed if no valid airspeed sensor is present
-outputs airspeed_validated topic
Signed-off-by: Silvan Fuhrer <silvan@auterion.com>