Support for parallel rollouts running in the background

[Tadinu]

Hi, may there be similar support for parallel rollouts in Genesis, which can run in the background, like in MuJoCo?
https://mujoco.readthedocs.io/en/stable/python.html#pyrollout
google-deepmind/mujoco#203
Related to #760 #464 #520 #1076 #1150

For now, one workaround is running 2 Genesis instances, one with renderer + one headless running rollouts of dynamics/planning asynchronously, communicating with each other using shared memory
https://github.com/vincekurtz/hydrax/blob/main/hydrax/simulation/asynchronous.py