[python] Improve viewer stability and reliability.
This release improves the stability of the viewer. In addition, it introduces a default color cycle when replying simulation for multiple robots at once (7 different colors).
Improvements:
- [python/viewer] Add default colors if multiple robot are replayed at the same time.
- [python/viewer] Redirect meshcat backend std_err to devnull to avoid flooding main thread.
Bug fixes:
- [core] Fix jiminy.Robot multiple initialize.
- [python/viewer] Fix edge case make the robot not appear in viewer if closed manually and reopen with same name.
- [python/viewer] Handle backend process kill timeout exceptions.
Miscellaneous:
- [misc] Disable automatic forward compatibility of numba to avoid potential install failure.