text: Title: [ENH] interface `simdkalman` filters as a panel transformer
  Body: Quite randomly I discovered the `simdkalman` package, which is an alternative to `pykalman` and `filterpy`, and the only package that offers - in `sktime` parlance - an optimized `Panel` mode (= collections of time series).
  https://github.com/oseiskar/simdkalman
  
  Since filters are one area of very commonly used pre-processing steps, it would be great to have an `sktime` native interface!
  
  The main options are:
  
  * directly in `sktime`, using the extension template https://www.sktime.net/en/latest/developer_guide/add_estimators.html
  * or, in `simdkalman` directly, and linking the estimator registry to the package so it appears in the estimator overview - this would require collaboration with the authors.
  
  FYI @oseiskar, @winedarksea, @microprediction.