Refactor camera demo

[caguero]

Refactors the camera demo leveraging the latest improvements in ros_gz.

• I replaced the previous launch file from Python to XML.

Summary

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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[ahcorde]

When RViz is opened the position of the camera is in the wrong position.

My suggestions here:

• The sdf file that we are using it's from gz-sim, and we need to define in the camera sensor the gz_frame_id to camera_optical
• Then we need to add a static transfrom

<node pkg="tf2_ros" exec="static_transform_publisher" args="--frame-id camera_link  --child-frame-id camera_link_optical --roll 1.570796327 --yaw 1.570796327" />

Let me know if you need some help and I can open a PR with the suggestions

[caguero]

When RViz is opened the position of the camera is in the wrong position.

My RViz camera looks the same as the one in Gazebo. Is this what you're seeing on your side?

[caguero]

When RViz is opened the position of the camera is in the wrong position.

To minimize changes, I used the default camera sensor frame in the static transform publisher so that we don't need to add any frame id and the example will still work with the default world.

Here's the 3D scene with the updated camera position: