Add `wemake-plain` output formatter

It should be the same as wemake, but without colors. Why?

When I try to save the output to file, I get this:

  106:29   WPS220 Found too deep nesting: 28 > 20
  try:
  ^

And I want to have this:

  106:29   WPS220 Found too deep nesting: 28 > 20
  try:
  ^

[sobolevn]

Or we can add NO_COLOR support https://no-color.org/ Which is better in my perspective

[sobolevn]

Output has color codes if outputted to the terminal

Correct!

Output doesn’t have color codes if piped into another program or a file

Well, that’s complicated. Because it might be very tricky. Different shells, different terminals, different OSes, different programs, different pipe methods, etc. I cannot say that it works. But, I cannot say that it does not work.

Presence of color codes depends solely on whether or not NO_COLOR environment variable is defined

Yes, this way we would have smooth way to control the output without the need to tweak the formatter manually.