Drop adde-lint, use sass-lint + prettier for "lint:sass" run script

[bantic]

Related to #1163.

This drops the adde-lint --sass in favor of using the underlying commands directly.

The adde-lint subcommand (defined here) runs both sass-lint and prettier:

https://github.com/Addepar/addepar-ember-toolbox/blob/897b838c696c422bdf70c81983e6ecc29db2e34b/lib/lint.js#L163-L166

which in turn are defined at:

https://github.com/Addepar/addepar-ember-toolbox/blob/897b838c696c422bdf70c81983e6ecc29db2e34b/lib/lint.js#L115-L140

I added a log line at https://github.com/Addepar/addepar-ember-toolbox/blob/897b838c696c422bdf70c81983e6ecc29db2e34b/lib/lint.js#L22 to double-check the exact commands that are run.

A few minor changes:

• expand the CLI flags to long form (--verbose --no-exit instead of -vq for sass-lint, --list-files for prettier)
• explicitly pass the config to sass-lint via --config flag

The glob paths passed to prettier are the same ones that adde-lint would -- it checks for presence of certain paths on disk and concats all the dirs it finds. I've left it the same for future-proofing, although there are no scss files in addon/.

Notes:

• The way this is setup (before and after this PR), there is no sass-lint-ing of the scss files for the tests dummy app. I did not enable that for this PR because it results in a handful of failures
• There are some .css files in this repo; they are not linted (via sass-lint or prettier). This PR doesn't change that