[cleanup] deleted files which may not be needed anymore

[davidcalderon03]

Description

This PR does the following:

• Deletes urc_gazebo
• Deletes everything in urc_platform except for the joystick driver
• Deletes unnecessary documents in the documents folder
• Removes urc_imu, urc_manipulation, and urc_scripts

Testing Steps

1. colcon build
2. . install/setup.bash
3. ros2 launch urc_bringup bringup.launch.py
4. ros2 launch urc_bringup bringup_simulation.launch.py

Expectation: The thing which does the thing does the thing

Self Checklist

• I have formatted my code using ament_uncrustify --reformat
• I have tested that the new behavior works

[davidcalderon03]

NOTE. The main concern as of now is that we need to move the STL files over to urc_hw_description, since they are pulled from urc_gazebo. Everything else in urc_gazebo (cpp files, launch scripts, other assets) should be deleted

[davidcalderon03]

Everything seems to work fine still, the only concern as of now is that we have two versions of the joystick driver, one is the old one in urc_platform and the new one Simon made in urc_scripts (which is a Python-translated version). I think we can keep both for now, but we need to discuss which one we would want to use moving forward (probably will be deleting urc_platform overall).