drivers/actuators/modalai_esc: update to use mixer module and control allocator properly

- update motor mapping to use new UART_ESC_FUNC* auto generated params
 - add support for actuator_test msg to support Actuator Testing in QGC
 - modalai_fc-vX targets start driver if configured
 - keep track of ESC spin direction in own param
 - set ramp up param in MixerOutput to false

boards/modalai/fc-v1/init/rc.board_sensors

@@ -3,6 +3,11 @@
 # ModalAI FC-v1 specific board sensors init
 #------------------------------------------------------------------------------
 
+if param greater UART_ESC_CONFIG 0
+then
+	modalai_esc start
+fi
+
 board_adc start
 
 # Start Digital power monitors

boards/modalai/fc-v2/init/rc.board_sensors

@@ -3,11 +3,10 @@
 # ModalAI FC-v2 specific board sensors init
 #------------------------------------------------------------------------------
 
-# VOXL ESC - TODO
-#if param greater UART_ESC_CONFIG 0
-#then
-#	modalai_esc -d /dev/ttyS4 start
-#fi
+if param greater UART_ESC_CONFIG 0
+then
+	modalai_esc start
+fi
 
 board_adc start