Shared altitude control function in position_control.c (#13954)

* Altitude control code shared

fewer debugs
subtract D

* remove #include comments, simplify coding, restructuring

thanks JP and MH

* fix cms limits for throttle control

* Use altitude_control debug, fix throttle calculation

minor refactoring

* use AUTO_CONTROL_ALTITUDE debug in place of GPS Rescue throttle pid

* use autopilot for position control names

* fixes from reviews - thanks

* Re-organise included files and functions thanks Karate

* missed init and other typos

* remove old unused unit test file, tidy up thanks Mark

* fix indentation on one line

src/main/fc/init.c

@@ -95,6 +95,7 @@
 #include "fc/tasks.h"
 
 #include "flight/alt_hold.h"
+#include "flight/autopilot.h"
 #include "flight/failsafe.h"
 #include "flight/imu.h"
 #include "flight/mixer.h"
@@ -102,7 +103,6 @@
 #include "flight/pid.h"
 #include "flight/pid_init.h"
 #include "flight/position.h"
-#include "flight/position_control.h"
 #include "flight/servos.h"
 
 #include "io/asyncfatfs/asyncfatfs.h"
@@ -828,7 +828,7 @@ void init(void)
 #endif
 
     positionInit();
-    positionControlInit(positionControlConfig());
+    autopilotInit(autopilotConfig());
 
 #if defined(USE_VTX_COMMON) || defined(USE_VTX_CONTROL)
     vtxTableInit();
@@ -1000,7 +1000,7 @@ void init(void)
     spiInitBusDMA();
 #endif
 
-// position_control must be initialised before modes that require the position_control pids
+// autopilot must be initialised before modes that require the autopilot pids
 #ifdef USE_ALT_HOLD_MODE
     altHoldInit();
 #endif