Add Gazebo simulation plug-in for Hesai XT-32 lidar

[2b-t]

This commit adds the lidar Gazebo simulation plug-in to the URDF of Hesai PandarXT (similar to the Ouster simulation in frontier_description by @mmattamala in ori-drs/frontier_description#9). The ranges are taken from the Pandar XT-32 brochure and user manual.

In order to test it launch the Hesai with the simulation flag set to true $ roslaunch hesai_description view_urdf.launch simulation:=true, launch Gazebo with roslaunch gazebo_ros mud_world.launch and finally spawn the model into Gazebo with $ rosrun gazebo_ros spawn_model -urdf -param /robot_description -model hesai. Finally add the lidar topic in Rviz.

Here a small preview of what this looks like:

HesaiGazebo.mp4

[mauricefallon]

@mmattamala : would you mind reviewing and merging these alphasense and hesai PRs for @2b-t ?
It should all be compatible with handheld Frontier and Spot mounted frontier.

@mcamurri might also have an opinion as he has a Frontier.

This is the other one:
ori-drs/alphasense_description#4

[mmattamala]

@2b-t The simulations works perfectly for me, thanks for putting this together. For the alphasense, I'll write comments directy in ori-drs/alphasense_description#4

[mcamurri]

Looks great, thanks!

Two minor comments (totally optional):

• I'm not sure why at line 25 the name of the sensor is hesai_pandar_xt-VLP
• The the name pandar has been removed from the XT product line some time ago. I'm not sure if you want to use this description for all hesai lidars or only the XT product line. In the last case, you might consider removing the pandar name. The mesh is obviously for the XT-32 model only.

[2b-t]

Resolved in #3.