Add more filter functions

[AlexandreHiroyuki]

• https://medium.com/deelvin-machine-learning/time-series-filtering-algorithms-a-brief-overview-af2d3112cd03
• https://bookdown.org/rdpeng/timeseriesbook/filtering-time-series.html

[AlexandreHiroyuki]

• add exponential moving average filtering

[AlexandreHiroyuki]

https://en.wikipedia.org/wiki/Moving_average#:~:text=An%20exponential%20moving%20average%20(EMA,decreases%20exponentially%2C%20never%20reaching%20zero.

[AlexandreHiroyuki]

• Add weighted moving average