Passing in a PWMOut still works but is deprecated. It will be
removed in CircuitPython 8.0.0
This also switches STM32 timer indices and channel indices to
0-based in our pin data rather than `- 1` everywhere. The latter is
more bug prone.
Most of the way for #3264
Tested on Metro M0, Metro M4, Feather S2, Feather nRF52840, Feather
STM32F4 and Arduino RP2040.
Restructures the STM port of Circuitpython to be more generic about the STM32 chip lines to support
the F7 and H7 series of chips. Adds the new Packages directory to organize different chip layouts
between lines. Makes general changes to the Makefile to condense board-level flags to the minimum
and support the new chip series. Adds the new chip line to the Peripherals directory, along with
new python tools used to generate peripheral text automatically in the tools/ directory.
