Use NPM style guide package

[hursey013]

The change needed to make this function when the app is deployed to the various envs has been added, so resubmitting this reverted PR.

Here is the previous PR for reference:

This uses the identity-style-guide NPM package to import shared assets. This first PR imports relatively low risk assets: font files, and favicons. A follow up PR will address shared stylesheets, images, and possibly some Javascript.

[zachmargolis]

LGTM