Add jsbsim bridge to enable jsbsim for px4 SITL on jsbsim (#15748)

* Add jsbsim bridge to enable jsbsim for px4 SITL/HIL on jsbsim

This is a PX4 HIL/SITL integration into JSBSim. JSBSim is an open source flight dynamics model (http://jsbsim.sourceforge.net/)

Currently there are three models available which is the rascal, quadrotor_x, hexarotor_x integrated into the bridge.

The simulation can be run with the firmware with the following command for example
```
make px4_sitl jsbsim_rascal
```

The visualization is done flightgear and is done by the bridge sending UDP packets to flightgear. To disable the visualization `HEADLESS=1` when running the make command.

The simulation can be configured through the configuration files under the `config` directory through a xml file. Senor configurations,  The xml file name should match the name of the model.

* Update Tools/sitl_run.sh

Co-authored-by: Beat Küng <beat-kueng@gmx.net>

Co-authored-by: Beat Küng <beat-kueng@gmx.net>

Tools/setup_jsbsim.bash

@@ -0,0 +1,40 @@
+#!/bin/bash
+#
+# Setup environment to make JSBSim visible to PX4.
+#
+# License: according to LICENSE.md in the root directory of the PX4 Firmware repository
+
+if [ "$#" != 3 ]; then
+    echo -e "usage: source setup_jsbsim.bash src_dir build_dir model\n"
+    return 1
+fi
+
+SRC_DIR="$1"
+BUILD_DIR="$2"
+MODEL="$3"
+
+export FG_AIRCRAFT="${SRC_DIR}/Tools/jsbsim_bridge/models"
+
+# This is needed for aircraft namespace mapping
+# Need more architectural discussions to make this more scalable
+case "$MODEL" in
+        rascal)
+            AIRCRAFT_DIR="Rascal"
+            MODEL_NAME="Rascal110-JSBSim"
+            ;;
+        quadrotor_x)
+            AIRCRAFT_DIR="quadrotor_x"
+            MODEL_NAME="quadrotor_x"
+            ;;
+        hexarotor_x)
+            AIRCRAFT_DIR="hexarotor_x"
+            MODEL_NAME="hexarotor_x"
+            ;;
+        *)
+            echo "Unknown Model"
+            exit 1
+
+esac
+
+export JSBSIM_AIRCRAFT_DIR="$AIRCRAFT_DIR"
+export JSBSIM_AIRCRAFT_MODEL="$MODEL_NAME"