Replace builtin color module with pygments

[iamdefinitelyahuman]

Overview

Remove brownie.utils.color in favor of pygments.

• color is an unnecessary reinvention of the wheel and adds to the code complexity.
• Using pygments will help ensure a consistent color scheme and remove an area of required opinions ("what color is best here?")

Specification

1. Completely remove brownie.utils.color.
2. Choose a lexer or set of lexers, document when and where to use them, and handle color with pygments.

Dependencies

Shouldn't break anything but will touch many files and significantly change the overall feel of Brownie. Definitely a v2.0.0 change.