Add aural label for "application" breadcrumb in crumbs

Summary: Ref T4843. This is a purely-visual link; label it with the application name.

Test Plan: {F149583}

Reviewers: btrahan, chad

Reviewed By: chad

Subscribers: epriestley

Maniphest Tasks: T4843

Differential Revision: https://secure.phabricator.com/D8927