Support Inkplate Arduino library (black and white)

[sbrin]

Inkplate Arduino is based on AdafruitGFX and it has the same API.

There is one important difference: the color has several brightness levels

the variable color represents color in grayscale of black mode. 0 represents black, 7 represents white and numbers in between represents shades; 1 is lightest grey, 6 represents darkest grey.

https://inkplate.readthedocs.io/en/latest/arduino.html

At first iteration we support only black and white version.

Please add

• a new platform Inkplate which copies all AdafruitGFX monochrome features
• every layer should have a color selector with values from 0 to 7
• • Black (0)
• • 1
• • 2
• • 3
• • 4
• • 5
• • 6
• • White (7)
• the canvas background must be white

The shades of grey are 256/7 and spread proportionally