[python/viewer] Fix meshcat backend.

[duburcqa]

• [core] Shuffle constraint solver iterations iif necessary, no matter if constraint set changes.
• [core] Move contact point at the interface with the ground for impulse model. ( [core] Move contact points with the ground at the interface for impulse model. #404)
• [core/python] Fix bindings signature of some controller's method.
• [python/plot] Fix missing grid for single plot tabs.
• [python/viewer] Fix viewer compatibility with meshcat>=0.3.1.
• [python/viewer] Increase meshcat recorder timeout.
• [python/viewer] Fix meshcat viewer 'has_gui' method.
• [python/viewer] Fix meshcat notebook viewer.
• [python/viewer] Properly close opening viewer if raises exception at init.
• [python/viewer] Add height map rendering capability to Panda3d backend.
• [python/viewer] Add support of jupyterlab and vscode notebooks locally using Meshcat backend.
• [gym/common] Check that simulation data is available before plotting.
• [gym/common] Fix 'play_interactive' not disabling 'is_training' flag.
• [gym/common] Add flag to 'play_interactive' to ignore 'is_done' state.
• [gym/rllib] Support obs normalization for PPO spatial regularization.
• [gym/rllib] Raise clear exception if observation space is not dict in PPO.
• [gym/rllib] Replace L2-norm temporal smoothness regularization by L1-norm.
• [gym/rllib] Fix L2 reg not backpropagating gradient.
• [gym/rllib] Scale spatial loss by observation distance.
• [misc] Fix CI dependency install.
• [misc] Relax ray version requirement.