Matches convention with cmd_vel and odom topics.

[francocipollone]

🎉 New feature

Related to #190

Summary

Matches cmd_vel and odom convention on topics. This enhances easier integration with other layers/technologies.

• Adds remapping to controller_manager's diff_controller node.
  • diff_controller/odom -> odom
  • diff_controller/cmd_vel_unstamped -> cmd_vel
• Removes dependency on twist mux

Checklist

• [x] Signed all commits for DCO
• [ ] Added tests
• [ ] Added example and/or tutorial
• [x] Updated documentation (as needed)
• [ ] Updated migration guide (as needed)
• [ ] Consider updating Python bindings (if it affects the public API)