Add tone generation example using PWM and piezo buzzer or a speaker

[jcarranz97]

NOTE - This PR depends on raspberrypi/pico-sdk#1569 as it uses pico\tone.h library.

This example demonstrates how to use the tone library to generate tones using a piezo buzzer or a speaker.

The tone() function is similar to tone() from Arduino.

In this example, the Raspberry Pi Pico performs "Silent Night" melody to demonstrate how to reproduce tones that become melodies 🎶 (I am using this to put some music on my Christmas Tree 🎄 🎅🏿 ).

Thanks!

[peterharperuk]

What piezo are you using? The only one I had sounds terrible!

[jcarranz97]

What piezo are you using? The only one I had sounds terrible!

It is basically a passive buzzer (which does not make any sound when you directly give power).
https://samueladesola.medium.com/how-to-play-the-musical-notes-on-the-arduino-1e9505d00c60#:~:text=Unlike%20the%20active%20buzzer%20that,%2C%20E%2C%20F%2C%20G.

[lurch]

As this now depends on raspberrypi/pico-extras#70 I believe this PR ought to be closed and a similar one re-opened on the https://github.com/raspberrypi/pico-playground repo @jcarranz97

EDIT: Converted this PR to draft to stop it being accidentally merged.