Highlight audited paths in commit detail

Summary:
This doesn't indicate which path is part of which package - I think it would be too heavy.
It just highlights the paths in a similar way as audits are highlighted.

Maybe we can use different colors for highlighting different packages and use them also in paths. We can mix the colors if one path is part of more packages :-).

Test Plan:
Viewed commit with 9 files and 4 packages where I am responsible only for one of them.
Verified that the only file in my package is highlighted.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin, haugen

Maniphest Tasks: T1226

Differential Revision: https://secure.phabricator.com/D2982