Strip down dependencies to minimum

[stoutheo]

• Move all examples .py and .launch that depend on other packages of ros-pybullet into a separate repo in the org.
• Prepare an installation script for the new repo that gets all dependencies and packages for examples.
• Prepare an installation script that is only for this repo (dependency on custom_ros_tools will remain).

[joaomoura24]

I would dare here to add that over time you should try to remove the dependencies on EXOTica, which is what takes most of the installation time.

[cmower]

Yup, also planning that ik_ros will be replaced with optas.