Updated micropython VGA library for the pico2 - 800x600 8 colors

[HughMaingauche]

Hello all,

I recently updated my micropython VGA library for the pico 2.

https://github.com/HughMaingauche/PICO2-VGA-Micropython

This is an upgrade of my previous VGA micropython display library, using the pico2 allows to use a VGA screen with a 800x600 resolution and 3 bits per pixel (8 colors).
This library uses 3 PIO statemachines and 2 DMA channels
A full framebuffer and a font, once loaded in memory, will leave approx 270k of available memory to do stuff and use a VGA monitor directly connected to the PICO

Other improvements are:

• Use of the DMA included library available in the standard micropython instead of direct registry modification used in my previous code
• Changed the font system to use xglcd fonts (from rdagger library)
• Added a plotting library to make real time plotting more easy

I tried to document the code as much as I could. I have no doubt that this can be optimized quite a lot.
If any of you is interested in using or improving it, i'll be happy to provide further explanations.

Hugh