[Feature] Add melody block

[laurensvalk]

Is your feature request related to a problem? Please describe. Our Python API has a nice way of playing melodies but this is not currently exposed in the block language.

Describe the solution you'd like Any ideas what this should look like?

In the most basic form, it could be a block with several notes, where you can click the white > arrow to add more notes, similar to the print block. Each input could be a string of the same kind as we use in Python.

The fancier version could have a piano-like input for each note, and show the total melody a sheet music when you are done editing.

Describe alternatives you've considered Import the method from Python.