Add MFLES from StatsForecast

[tblume1992]

MFLES is a newer model that was implemented in Nixtla's statsforecast:
https://nixtlaverse.nixtla.io/statsforecast/docs/models/mfles.html

Since there are other StatsForecasts methods (theta/ets/arima etc) hopefully it is easy to add this as well!

Let me know if there are any questions with parameters or the implementation.

[dennisbader]

Hi @tblume1992 and thanks for this feature request. Yes, it looks like it should be rather straight-forward to add it.
Is this something you'd like to contribute to? We recently added TBATS from SF in #2611, the implementation would look very similar to that one :)

[tblume1992]

@dennisbader - I probably won't have time in the near future - but if no one can get to it in a bit I can take a shot! Preferably it can be done before then though!