Backporting fixes:
- remove kwargs from hybrid_forward input name inference (#846)
- Fix the quantiles used to compute MSIS (#849)
- Fix to_time_series_item in splitter (#874)
- updated Pandas deprecation (#875)
- Updated Frequency String for Pandas Timestamp (#884)
- splitting features and uses DataEntry instead of TimeSeriesItem (#890)
- fix multiprocessing in backtest function (#915)
- Fix LDS distribution for the case where sequence_length==1 (#921)
- Defaulting MSIS to NaN when it can't be calculated. (#923)