Add PicoDVI support

[tannewt]

PicoDVI in CP support 640x480 and 800x480 on Feather DVI, Pico and Pico W. 1 and 2 bit grayscale are full resolution. 8 and 16 bit color are half resolution.

Memory layout is modified to give the top most 4k of ram to the second core. Its MPU is used to prevent flash access after startup.

The port saved word is moved to a watchdog scratch register so that it doesn't get overwritten by other things in RAM.

Right align status bar and scroll area. This normally gives a few pixels of padding on the left hand side and improves the odds it is readable in a case. Fixes #7562

Fixes c stack checking. The length was correct but the top was being set to the current stack pointer instead of the correct top. Fixes #7643

This makes Bitmap subscr raise IndexError instead of ValueError when the index arguments are wrong.

[bill88t]

The part where it fixes the stack crashes, has been tested by me and and Retiredwizard, across all esp mcu's.

[RetiredWizard]

Tested new stack code on RP2040 and SAMD51, no issues....

This is from the PR artifact using adafruit_turtle:

[dhalbert]

Great! Code looks good for consistency, etc. Other people tested the actual video, so I did not do that.

[jposada202020]

As discussed in Discord.. I think I reduced the code as much as I can... hopefully

Tested in
Adafruit CircuitPython 8.1.0-beta.1-36-g7d02bff6b on 2023-04-20; Adafruit Feather RP2040 DVI with rp2040

Problem

import board
import displayio
from bitmaptools import draw_line
display = board.DISPLAY
group = displayio.Group()

palette = displayio.Palette(1)
palette[0] = 0xFFFFFF

a2 = displayio.Group(x=0, y=0, scale=1)
a2bitmap = displayio.Bitmap(300, 300, 2)
tile2 = displayio.TileGrid(a2bitmap, pixel_shader=palette, x=0, y=0)
draw_line(a2bitmap, 1, 1, 1, 300, 1)
draw_line(a2bitmap, 1, 1, 200, 200, 1,)
a2.append(tile2)
group.append(a2)

display.show(group)

So Not sure if my display resolution is all wrong, but I should get 640x480? If it is my mistake, sorry :).
However this script works fine in the Pyportal Titano https://github.com/jposada202020/CircuitPython_uplot/blob/main/examples/uplot_readme_example.py
But with the DVI is blown-up and some of the plots could not be seen.

[dglaude]

The above message from @jposada202020 is discussed in #7894 (and is now a closed issue).

As discussed in Discord.. I think I reduced the code as much as I can... hopefully