ROS Integration Pages

[quarkytale]

Checklist:

• [x] Replicate for fortress, garden, harmonic
• [x] Add RViz ros_gz_bridge demo
• [x] How-to-use guide on the template package
• [x] Add a page on using joint_state_publisher_gui
• [x] Tutorial explaining implementation of RViz ros_gz_bridge demo
• ~[ ] Add nested pages~
• [x] Separate ~page~ section for installing the models directory and exporting the paths
• [x] Add reference usage of DSV file with an example
• [x] Add screenshot/gif of joint_state_publisher_gui
• [x] Elaborate folder structure of template
• [x] Test compatibility with Fortress
• [ ] Launching simulation with ROS 2 launch
  • [ ] How to use launch parameters
  • [ ] Reusing launch files
  • [ ] ros_gz bridge in launch files (but we should promote the yaml file approach).