Honour `NO_COLOR` environment variable alongside `CLICOLOR`

[mkaput]

While this crate follows https://bixense.com/clicolors/, several crates in the ecosystem (for example tracing) follow another convention of forcing tools not to print coloured output: https://no-color.org/

I wonder if it wouldn't be feasible to support both conventions simultaneously in this crate. The unknown question is which convention should be prioritized. Personally, I think it doesn't matter and would probably check NO_COLOR after CLICOLOR.

Relevant code, as far as I see, is only this chunk:

console/src/utils.rs

Lines 19 to 23 in de2f15a

	fn default_colors_enabled(out: &Term) -> bool {
	(out.features().colors_supported()
	&& &env::var("CLICOLOR").unwrap_or_else(|_| "1".into()) != "0")
	|| &env::var("CLICOLOR_FORCE").unwrap_or_else(|_| "0".into()) != "0"
	}