Move airspeed_selector module into sensors module

with the main goal to save resources like flash, RAM, CPU.

src/modules/airspeed_selector/Kconfig

@@ -1,12 +0,0 @@
-menuconfig MODULES_AIRSPEED_SELECTOR
-	bool "airspeed_selector"
-	default n
-	---help---
-		Enable support for airspeed_selector
-
-menuconfig USER_AIRSPEED_SELECTOR
-	bool "airspeed_selector running as userspace module"
-	default y
-	depends on BOARD_PROTECTED && MODULES_AIRSPEED_SELECTOR
-	---help---
-		Put airspeed_selector in userspace memory

src/modules/sensors/CMakeLists.txt

@@ -91,6 +91,8 @@ endif()
 
 if(CONFIG_SENSORS_VEHICLE_AIRSPEED)
 	target_link_libraries(modules__sensors PRIVATE airspeed)
+	add_subdirectory(airspeed_selector)
+	target_link_libraries(modules__sensors PRIVATE airspeed_selector)
 endif()
 
 if(CONFIG_SENSORS_VEHICLE_ANGULAR_VELOCITY)

src/modules/sensors/airspeed_selector/CMakeLists.txt

@@ -30,13 +30,11 @@
 # POSSIBILITY OF SUCH DAMAGE.
 #
 ############################################################################
-px4_add_module(
-	MODULE modules__airspeed_selector
-	MAIN airspeed_selector
-	SRCS
-		airspeed_selector_main.cpp
-		AirspeedValidator.cpp
-		AirspeedValidator.hpp
-	DEPENDS
-		wind_estimator
+
+px4_add_library(airspeed_selector
+	airspeed_selector_main.cpp
+	AirspeedValidator.cpp
+	AirspeedValidator.hpp
 )
+
+target_link_libraries(airspeed_selector PRIVATE wind_estimator)