Fix stage for pygamer and pybadge on CP 7.0

Backlight handling is broken in displayio, so we handle it ourselves.
The keypad now requires additional parameters.

Works around adafruit/circuitpython#5476

Add the font generation and examples

Add support for Pimoroni PicoSystem

Add support for scaled displays

Allows to use 2x2 pixels on larger displays.
Also fix some bounds checking code.

Allow use of audiopwmio in place of audioio

Add support for Meowbit

Add set_next_code_file to pygamer and pybadge

Update pybadge and pygamer to use keypad module instead of gamepadshift

Update pybadge and pygamer to use keypad module instead of gamepadshift

Update pybadge and pygamer to use keypad module instead of gamepadshift