ROS2 workspace setup

download dependencies (px4_msgs and traj_gen):
- px4_msgs : checkout the right version. For px4 v1.15, main branch of px4_msgs throws serialization errors and there is no branch in px4_msgs for px4 v1.15. We checkout a specific commit instead.
```
cd ros2_code
git clone https://github.com/PX4/px4_msgs.git src/px4_msgs
cd src/px4_msgs
git checkout bd9dc0fae0162960a31af8f232a9e9f85522ae73
cd ../..
```
- traj_gen (optional): used to generate desired trajectory to be executed by the UAV
```
cd ros2_code
git clone https://github.com/TareqAlqutami/traj_gen.git src/traj_gen
```
source ROS2

You can use a script to source ros2. We already have one script to source foxy:
```
source ../scripts/source_ros2.bash
```
Build ros2_code colcon workspace

Add the symlink-install flag to allow us to modify the python code and rerun without the need to rebuild
```
colcon build --symlink-install
```
You may see some warnings. But as long as there are no errors it should be OK.

Test the code by launching rviz visualization of robot urdf

source install/setup.bash
ros2 launch am_description display.launch.py

you can specify the urdf model using urdf_model. Note that you will need to provide complete path such as

ros2 launch am_description display.launch.py urdf_model:=src/am_description/urdf/tilted_hex_arm.urdf

Explore using kinematics with KDL library in am_description/scripts/kdl_testing.ipynb
More details of each ROS2 package and nodes within is found in the ros2 workspace readme here. Running full SITL simulation with offboard control is described there.