Add a smoothing function on the detected frequency so the UI doesn't jump around as much

[joulupukki]

The ADC sampling happens at 48kHz and as soon as we detect a frequency, we're making it available to the UI. The UI updates every 100ms. The smoothing we currently have isn't sufficient and it might be nice to have an additional smoothing on the frequency output so by the time it reaches the UI, the jumps aren't as drastic or as much.

The key is to get the pitch detection to be as stable & fast as possible and make the UI indicate that.

One of the things we may be up against is that the ESP32 ADC isn't the best compared with other SOCs out there. But, this is all part of the "fun" challenge of using a readily-available and inexpensive SOC.

[joulupukki]

I did a little bit of work on this Saturday, Dec 7. The latest in main as of right now is fairly decent, though I think it can be still improved. I turned on Q DSP’s signal_conditioner again with default values and that runs before the data is sent to the pitch detector. I also adjusted the config of the 1EU and Simple Exp filters. I swapped the order that those filters run so that the 1EU filter runs first.