Port MARSIM to ROS 2

[Jaeyoung-Lim]

Problem Descrption
ROS 1 has reached its EOL in May 2025. Therefore, it would be great to have ROS 2 support for MARSIM.

Additionally, recent robotics implementations have been moving towards ROS 2 as well.

Solution
This commit ports MARSIM to ROS 2.

Not all functionalities might be working for ROS 2.
However, the ROS 2 implementation can be tested with the following launch file.

ros2 launch test_interface single_drone_mid360.launch.py

Fixes #13 #25

Additional Context

• This implementation was done to test lidar inertial odometry with the PX4 Autopilot

[jackykongfz]

Pretty much thanks to Lim's large support for attaching MARSIM to ROS2!!!! I have created a branch ubuntu20_ros2 to maintain it. Since I do not have ROS2 environment now so the code is not tested locally yet, I will close this pull request until I test it.

[Jaeyoung-Lim]

@jackykongfz Great, thanks. Glad to see that you find it useful.

Given the large differences in the implementation, I think it might be easier to maintain on a separate repo (e.g. MARSIM2). However, I leave the decision up to you.

[xxl1998]

@Jaeyoung-Lim Thanks for your work on porting MARSIM to ROS2, this saved much of my time.
But I still found some issues in your code.
1: The launch uses absolute path to find .pcd, so it can not run on other's computer;
2: The broken dependency makes compile error;
3: A default param makes cascadePID diverge;
4: The UAV model was not in rviz.
So I made some small modification based on your code, and I will create a PR later to merge it to this repository.

[Jaeyoung-Lim]

@xxl1998 Thank you for pointing out the limitation of this PR. It would be great if you can make a PR against this PR such that we can keep track of the changes.

[shupx]

I have noticed that there is a ROS2 implementation of MARSIM in SUPER (https://github.com/hku-mars/SUPER/tree/master/mars_uav_sim). Is there any difference between that with this repo?