Add configurations for Zephyr SITL. Add init script for Zephyr SITL. Update...

Add configurations for Zephyr SITL. Add init script for Zephyr SITL. Update hexa_x.main.mix with leg control.

ROMFS/px4fmu_common/mixers/hexa_x.main.mix

 # Hexa X
 
 R: 6x 10000 10000 10000 0
+
+# mixer for left leg
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 7      0  20000 -10000 -10000  10000
+
+# mixer for right leg
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 8      0  20000 -10000 -10000  10000
+

ROMFS/sitl/mixers/delta_wing_sitl.main.mix

+Mixer for SITL plane
+=========================================================
+
+Z:
+
+Z:
+
+# mixer for the rudder
+M: 1
+O:       10000   10000   0 -10000  10000
+S: 0 2   10000   10000    0 -10000  10000
+
+# mixer for the flaps
+M: 1
+O:       10000   10000   0 -10000  10000
+S: 0 4   10000   10000    0 -10000  10000
+
+# mixer for the pusher/puller throttle
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 3      0  20000 -10000 -10000  10000
+
+# mixer for the left aileron
+M: 2
+O:      10000  10000   0 -10000  10000
+S: 0 0 -4000  -4000    0 -10000  10000
+S: 0 1  10000  10000   0 -10000  10000
+
+# mixer for the right aileron
+M: 2
+O:      10000  10000   0 -10000  10000
+S: 0 0  4000   4000    0 -10000  10000
+S: 0 1  10000  10000   0 -10000  10000
+
+# mixer for the elevator
+M: 1
+O:      10000  10000   0 -10000  10000
+S: 0 1 -10000 -10000   0 -10000  10000

posix-configs/SITL/init/rcS_gazebo_delta_wing

+uorb start
+param load
+param set MAV_TYPE 1
+param set SYS_AUTOSTART 3033
+param set SYS_RESTART_TYPE 2
+dataman start
+param set BAT_N_CELLS 3
+param set CAL_GYRO0_ID 2293768
+param set CAL_ACC0_ID 1376264
+param set CAL_ACC1_ID 1310728
+param set CAL_MAG0_ID 196616
+param set CAL_GYRO0_XOFF 0.01
+param set CAL_ACC0_XOFF 0.01
+param set CAL_ACC0_YOFF -0.01
+param set CAL_ACC0_ZOFF 0.01
+param set CAL_ACC0_XSCALE 1.01
+param set CAL_ACC0_YSCALE 1.01
+param set CAL_ACC0_ZSCALE 1.01
+param set CAL_ACC1_XOFF 0.01
+param set CAL_MAG0_XOFF 0.01
+param set SENS_BOARD_ROT 8
+param set SENS_DPRES_OFF 0.001
+param set SENS_BOARD_X_OFF 0.000001
+param set COM_RC_IN_MODE 1
+param set NAV_DLL_ACT 2
+param set NAV_ACC_RAD 15.0
+param set FW_THR_IDLE 0.6
+param set FS_GCS_ENABLE 2
+replay tryapplyparams
+simulator start -s
+rgbledsim start
+tone_alarm start
+gyrosim start
+accelsim start
+barosim start
+adcsim start
+gpssim start
+measairspeedsim start
+pwm_out_sim mode_pwm
+sleep 1
+sensors start
+commander start
+navigator start
+ekf2 start
+fw_pos_control_l1 start
+fw_att_control start
+land_detector start fixedwing
+mixer load /dev/pwm_output0 ../../../../ROMFS/sitl/mixers/delta_wing_sitl.main.mix
+mavlink start -u 14556 -r 2000000
+mavlink start -u 14557 -r 2000000 -m onboard -o 14540
+mavlink stream -r 80 -s POSITION_TARGET_LOCAL_NED -u 14556
+mavlink stream -r 80 -s LOCAL_POSITION_NED -u 14556
+mavlink stream -r 80 -s GLOBAL_POSITION_INT -u 14556
+mavlink stream -r 80 -s ATTITUDE -u 14556
+mavlink stream -r 80 -s ATTITUDE_QUATERNION -u 14556
+mavlink stream -r 80 -s ATTITUDE_TARGET -u 14556
+mavlink stream -r 20 -s RC_CHANNELS -u 14556
+mavlink stream -r 250 -s HIGHRES_IMU -u 14556
+mavlink stream -r 10 -s OPTICAL_FLOW_RAD -u 14556
+sdlog2 start -r 200 -e -t -a
+mavlink boot_complete
+replay trystart