Add icons to the new repository edit nav
Summary:
Ref T10748. These:
- Look nice.
- Hint at panel contents / effects.
- Hint which panels have been customized.
- Allow panels with issues or errors to be highlighted with an alert/attention icon.
Test Plan: {F1256156}
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T10748
Differential Revision: https://secure.phabricator.com/D15836