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/RcChannels.msg

@@ -0,0 +1,40 @@
+uint64 timestamp						# time since system start (microseconds)
+
+uint8 FUNCTION_THROTTLE      = 0
+uint8 FUNCTION_ROLL          = 1
+uint8 FUNCTION_PITCH         = 2
+uint8 FUNCTION_YAW           = 3
+uint8 FUNCTION_RETURN        = 4
+uint8 FUNCTION_LOITER        = 5
+uint8 FUNCTION_OFFBOARD      = 6
+uint8 FUNCTION_FLAPS         = 7
+uint8 FUNCTION_AUX_1         = 8
+uint8 FUNCTION_AUX_2         = 9
+uint8 FUNCTION_AUX_3         = 10
+uint8 FUNCTION_AUX_4         = 11
+uint8 FUNCTION_AUX_5         = 12
+uint8 FUNCTION_AUX_6         = 13
+uint8 FUNCTION_PARAM_1       = 14
+uint8 FUNCTION_PARAM_2       = 15
+uint8 FUNCTION_PARAM_3_5     = 16
+uint8 FUNCTION_KILLSWITCH    = 17
+uint8 FUNCTION_TRANSITION    = 18
+uint8 FUNCTION_GEAR          = 19
+uint8 FUNCTION_ARMSWITCH     = 20
+uint8 FUNCTION_FLTBTN_SLOT_1 = 21
+uint8 FUNCTION_FLTBTN_SLOT_2 = 22
+uint8 FUNCTION_FLTBTN_SLOT_3 = 23
+uint8 FUNCTION_FLTBTN_SLOT_4 = 24
+uint8 FUNCTION_FLTBTN_SLOT_5 = 25
+uint8 FUNCTION_FLTBTN_SLOT_6 = 26
+uint8 FUNCTION_ENGAGE_MAIN_MOTOR = 27
+
+uint8 FUNCTION_FLTBTN_SLOT_COUNT = 6
+
+uint64 timestamp_last_valid					# Timestamp of last valid RC signal
+float32[18] channels						# Scaled to -1..1 (throttle: 0..1)
+uint8 channel_count						# Number of valid channels
+int8[28] function						# Functions mapping
+uint8 rssi							# Receive signal strength index
+bool signal_lost						# Control signal lost, should be checked together with topic timeout
+uint32 frame_drop_count						# Number of dropped frames