Updated documentation for Humble.

[Umar-Azam]

I found some outdated documentation on the simulation page while reading through it. Small change editing out text mentioning incompatibility with humble. Possibly consider combining files "turtlebot4_simulator.md" and "simulation.md" for more concise documentation.

[roni-kreinin]

Good catch. We will update this page further to include the correct bringup launch file for Humble, as well as add documentation on some of the new features.