msg ROS2 compatibility, microdds_client improvements (timesync, reduced code size, added topics, etc), fastrtps purge

- update all msgs to be directly compatible with ROS2
 - microdds_client improvements
   - timesync
   - reduced code size
   - add to most default builds if we can afford it
   - lots of other little changes
 - purge fastrtps (I tried to save this multiple times, but kept hitting roadblocks)

msg/ActuatorTest.msg

@@ -0,0 +1,21 @@
+uint64 timestamp				# time since system start (microseconds)
+
+# Topic to test individual actuator output functions
+
+uint8 ACTION_RELEASE_CONTROL = 0	# exit test mode for the given function
+uint8 ACTION_DO_CONTROL = 1			# enable actuator test mode
+
+uint8 FUNCTION_MOTOR1 = 101
+uint8 MAX_NUM_MOTORS  = 12
+uint8 FUNCTION_SERVO1 = 201
+uint8 MAX_NUM_SERVOS  = 8
+
+uint8 action					# one of ACTION_*
+uint16 function					# actuator output function
+float32 value					# range: [-1, 1], where 1 means maximum positive output,
+								# 0 to center servos or minimum motor thrust,
+                   				# -1 maximum negative (if not supported by the motors, <0 maps to NaN),
+                   				# and NaN maps to disarmed (stop the motors)
+uint32 timeout_ms				# timeout in ms after which to exit test mode (if 0, do not time out)
+
+uint8 ORB_QUEUE_LENGTH = 8