Parse (mounted) camera info from MJCF file

[dzc0919]

Hi guys,thanks for releasing Roboverse, nice job!

I encountered a limitation when using the self.cameras interface in your simulator framework.

Currently, self.cameras only allows manually defining camera positions and orientations in world coordinates (via ScenarioCfg). However, it does not support loading cameras defined in the MJCF XML files (e.g., inside a ). This causes major issues in robotic settings where cameras are often attached to robot bodies (like head-mounted or end-effector cameras), and need to move along with them.

Additionally,ensure compatibility with scoped camera names like "xx/head_camera".

[Fisher-Wang]

Thank you, this is a good suggestion!