Make sure the Patternist process can generate some C++ code for Arduino

[aalex]

Make sure the Patternist process can generate some C++ code for Arduino

Tech details

• If we override some methods of the CodeWriter class in the Patternist class, we can write the code to serialize the MIDI notes into C++ code. Like this: https://github.com/ossia/score/blob/wip/pico-next/src/plugins/score-plugin-automation/Automation/AutomationModel.cpp#L352
• Let't keep the code of that process in score.
• Let's not write a unit test for it.
• The code is at:
  • https://github.com/ossia/score/blob/master/src/plugins/score-plugin-midi/Patternist/PatternExecutor.cpp
• Here is one process that is already implemented using cavendish. (we might not need that) MIDI reader already implemented : https://github.com/celtera/avendish/blob/main/examples/Advanced/MidiScaler/MidiReader.hpp
• We use https://fmt.dev/11.0/ to format strings for the C++ code.

[aalex]

Simply override the ProcessModel::codeWriter method.