Add support for heart rate for 100Hz PPG

[nitin710]

Describe the bug
HR uses a FIR filter, with hardcoded filter coefficients.

The frequency response changes when PPG sensor is run at different frequencies

Since, the frequency response is different, the following MAX peak detector will have different performance to PPG running at 100HZ vs 25Hz

[nitin710]

Thread for options for new libraries to implement IIR filters:

1. https://github.com/tttapa/Filters
2. https://github.com/mozanunal/SimpleDSP
3. https://github.com/JonHub/Filters
   • http://www.schwietering.com/jayduino/filtuino/index.php?characteristic=bu&passmode=lp&order=1&usesr=usesr&sr=25&frequencyLow=0.5&noteLow=&noteHigh=&pw=pw&calctype=float&run=Send

[nitin710]

Going ahead with https://github.com/tttapa/Arduino-Filters because

• It has a later commit
• Decent fork and stars
• The Filter usage looks more appealing
  • as compared to the other library which has specific function calls FilterOnePole