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/drivers/lights/blinkm/blinkm.cpp

@@ -256,7 +256,7 @@ extern "C" __EXPORT int blinkm_main(int argc, char *argv[]);
 
 BlinkM::BlinkM(int bus, int blinkm) :
 	I2C("blinkm", BLINKM0_DEVICE_PATH, bus, blinkm, 100000),
-	ScheduledWorkItem(px4::device_bus_to_wq(get_device_id())),
+	ScheduledWorkItem(MODULE_NAME, px4::device_bus_to_wq(get_device_id())),
 	led_color_1(LED_OFF),
 	led_color_2(LED_OFF),
 	led_color_3(LED_OFF),

src/drivers/lights/rgbled/rgbled.cpp

@@ -105,7 +105,7 @@ extern "C" __EXPORT int rgbled_main(int argc, char *argv[]);
 
 RGBLED::RGBLED(int bus, int rgbled) :
 	I2C("rgbled", RGBLED0_DEVICE_PATH, bus, rgbled, 100000),
-	ScheduledWorkItem(px4::device_bus_to_wq(get_device_id()))
+	ScheduledWorkItem(MODULE_NAME, px4::device_bus_to_wq(get_device_id()))
 {
 }
 

src/drivers/lights/rgbled_ncp5623c/rgbled_ncp5623c.cpp

@@ -105,7 +105,7 @@ extern "C" __EXPORT int rgbled_ncp5623c_main(int argc, char *argv[]);
 
 RGBLED_NPC5623C::RGBLED_NPC5623C(int bus, int rgbled) :
 	I2C("rgbled1", RGBLED1_DEVICE_PATH, bus, rgbled, 100000),
-	ScheduledWorkItem(px4::device_bus_to_wq(get_device_id()))
+	ScheduledWorkItem(MODULE_NAME, px4::device_bus_to_wq(get_device_id()))
 {
 }
 

src/drivers/lights/rgbled_pwm/rgbled_pwm.cpp

@@ -88,7 +88,7 @@ RGBLED_PWM *g_rgbled = nullptr;
 
 RGBLED_PWM::RGBLED_PWM() :
 	CDev("rgbled_pwm", RGBLED_PWM0_DEVICE_PATH),
-	ScheduledWorkItem(px4::wq_configurations::lp_default)
+	ScheduledWorkItem(MODULE_NAME, px4::wq_configurations::lp_default)
 {
 }