add full support for ANSI SGR escape sequences

This is for adding color to the text output salt emits in various
contexts including support for extended colors (256 and 256^3) and a few
other common text modifiers like bold, italic, underline, etc.

The code is put in salt/textformat.py (rather than
salt/utils/textformat.py) in order to allow for logging to import
TextFormat without loading all of salt/utils/__init__.py and causing
logging failures.
finally remove global, unused color declarations
update color name consistency
add color to console logger
pylint fixes
pylint again (why was this not caught the first time?)
remove misleading unicode message
fix utils unit test
Merge pull request #19265 from jfindlay/log_color

add color option to console logger