Gazebo Performance Tuning Guide

I know I've run into GZ performance issues with the TB4, and [others seem to have the same problems]([#Gazebo General > Performance of gazebo harmonic vs newer versions](https://openrobotics.zulipchat.com/#narrow/channel/526040-Gazebo-General/topic/Performance.20of.20gazebo.20harmonic.20vs.20newer.20versions/with/574577895)).

There is a laundry list of potential modifications to stock Gazebo that can address these issues, including:

- Swapping Ogre for Ogre 2
- Swapping the physics engine to Bullet Featherstone
- Using simpler models
- [Adding hardware acceleration](https://github.com/RobotecAI/RGLGazeboPlugin) for various functions.
- Performing [LIDAR simulation on a GPU](https://github.com/arjo129/gz_wgpu_rt_lidar/)
- Disabling PBR
- Many more that I am probably not aware of.

## Desired behavior

We should create a guide that walks users through enabling these changes to improve their Gazebo performance / RTF.