sitl: use lockstep components API

- avoids the need for ekf2_timestamp publications by q and lpe
- adds logger to the lockstep cycle and makes it poll on ekf2_timestamps
  or vehicle_attitude. This avoids dropped samples (required for replay).

ROMFS/px4fmu_common/init.d-posix/rcS

@@ -32,7 +32,8 @@ set PWM_OUT                     none
 set SDCARD_MIXERS_PATH          etc/mixers
 set USE_IO                      no
 set VEHICLE_TYPE                none
-set LOGGER_BUF			1000
+set LOGGER_ARGS                 ""
+set LOGGER_BUF                  1000
 
 set RUN_MINIMAL_SHELL           no
 
@@ -287,6 +288,12 @@ mavlink start -x -u $udp_onboard_payload_port_local -r 4000 -f -m onboard -o $ud
 [ -e "$autostart_file".post ] && sh "$autostart_file".post
 
 # Run script to start logging
+if param compare SYS_MC_EST_GROUP 2
+then
+	set LOGGER_ARGS "-p ekf2_timestamps"
+else
+	set LOGGER_ARGS "-p vehicle_attitude"
+fi
 sh etc/init.d/rc.logging
 
 mavlink boot_complete

ROMFS/px4fmu_common/init.d/rc.logging

@@ -16,17 +16,17 @@ fi
 
 if param compare SDLOG_MODE 1
 then
-	set LOGGER_ARGS "-e"
+	set LOGGER_ARGS "${LOGGER_ARGS} -e"
 fi
 
 if param compare SDLOG_MODE 2
 then
-	set LOGGER_ARGS "-f"
+	set LOGGER_ARGS "${LOGGER_ARGS} -f"
 fi
 
 if param compare SDLOG_MODE 3
 then
-	set LOGGER_ARGS "-x"
+	set LOGGER_ARGS "${LOGGER_ARGS} -x"
 fi
 
 if ! param compare SDLOG_MODE -1