px4_work_queue: command line status output and shutdown empty queues

* 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

src/modules/airspeed_selector/airspeed_selector_main.cpp

@@ -137,8 +137,6 @@ private:
 	bool _scale_estimation_previously_on{false}; /**< scale_estimation was on in the last cycle */
 
 	perf_counter_t _perf_elapsed{};
-	perf_counter_t _perf_interval{};
-
 
 	DEFINE_PARAMETERS(
 		(ParamFloat<px4::params::ARSP_W_P_NOISE>) _param_west_w_p_noise,
@@ -170,13 +168,12 @@ private:
 
 AirspeedModule::AirspeedModule():
 	ModuleParams(nullptr),
-	ScheduledWorkItem(px4::wq_configurations::lp_default)
+	ScheduledWorkItem(MODULE_NAME, px4::wq_configurations::lp_default)
 {
 	// initialise parameters
 	update_params();
 
 	_perf_elapsed = perf_alloc_once(PC_ELAPSED, "airspeed_selector elapsed");
-	_perf_interval = perf_alloc_once(PC_INTERVAL, "airspeed_selector interval");
 }
 
 AirspeedModule::~AirspeedModule()
@@ -184,7 +181,6 @@ AirspeedModule::~AirspeedModule()
 	ScheduleClear();
 
 	perf_free(_perf_elapsed);
-	perf_free(_perf_interval);
 
 	if (_airspeed_validator != nullptr) {
 		delete[] _airspeed_validator;
@@ -216,7 +212,6 @@ AirspeedModule::task_spawn(int argc, char *argv[])
 void
 AirspeedModule::Run()
 {
-	perf_count(_perf_interval);
 	perf_begin(_perf_elapsed);
 
 	/* the first time we run through here, initialize N airspeedValidator
@@ -572,7 +567,6 @@ and also publishes those.
 int AirspeedModule::print_status()
 {
 	perf_print_counter(_perf_elapsed);
-	perf_print_counter(_perf_interval);
 
 	int instance = 0;
 	uORB::SubscriptionData<airspeed_validated_s> est{ORB_ID(airspeed_validated), (uint8_t)instance};