Update Button class to match debouncer logic

[Neradoc]

• Button.short_count and Button.long_press now return a consistent value that only changes when Button.update() is called, like rose and fell do. This is important for the logic of the debouncer to work, where the status of the button should be stable during a "frame".

• The active_down parameter is changed to value_when_pressed, a clearer name with the opposite value (also used in the keypad module). With active_downset to True, the active value when the button is pressed is False.

• Expose Button.pressed and Button.released, while rose/fell remain the lower level signal direction of the edge.

Note that short_count changes value after the short_duration_ms delay, so as to not report a double click as a simple click, so you would either use pressed/released if you don't look for double clicks or short_count == 1 to detect a click, 2 for a double-click and more. Is that confusing ?

Maybe value_when_pressed and pressed/released could be moved into the Debouncer class.

• Improve the documentation of the Button class, with init parameters description.
• Update the gitignore to current cookiecutter while I'm here doing tests with sphinx (.env, _build, etc.)

[FoamyGuy]

Looks good to me. I tested these changes successfully with RP2040 and NeoKey Featherwing.

I do think the name value_when_pressed is more clear. and the way that short presses work does make sense to me as well.

Thanks @Neradoc