Redesign Config Application

Summary: Ref T11132, significantly cleans up the Config app, new layout, icons, spacing, etc. Some minor todos around re-designing "issues", mobile support, and maybe another pass at actual Group pages.

Test Plan: Visit and test every page in the config app, set new items, resolve setup issues, etc.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam, Korvin

Maniphest Tasks: T11132

Differential Revision: https://secure.phabricator.com/D16468