Stylelint: Consider ignoring `@media` when parsing max-nesting rule

Currently, we have a `max-nesting` rule that is very strict at only allowing 2 levels of nesting with `scss`, with the exception of `blockless-at-rules`. I think it might be beneficial to loosen this just a bit for `@media` rules by adding `"ignoreAtRules": ["media"]` to the general rule in Stylelint.

Stylelint currently already ignores `@media` at the first level in a nesting pattern when parsing for nesting depth, but it does not ignore `@media` when it resides down the chain. If we make the proposed change, `@media` levels will not affect the nesting depth evaluation, and we still shouldn't end up with too-specific of selectors.

Thoughts?

cc @peterwilsoncc @sambulance @goldenapples @rmccue @joemcgill @kirstyburgoine