HP41 TULIP4041 update

[MeindertKuipers]

Since the sources are in a more or less stable state (pending any feedback from Sylvain) I decided to make these public already at https://github.com/mjakuipers/TULIP-DevBoard. A binary for direct downloading in the Pico is in the build directory.

The usual disclaimer applies, use at your own risk. Also keep in mind that many parts are in development and half finished. Feedback is appreciated of course.

I still have not received my Pico 2 board, and I have some trouble getting the current sources to compile under the new SDK 2.0, and I am still using the SDK 1.51 for that.