Implement fancy breadcrumbs in new files

closes: CNVS-15249 CNVS-15372

test plan:
go to new files and make sure the breadcrumbs look like blakes mockups
especially try it when you have a bunch of crumbs and a small screen
it should have a '...' that opens in a drop down.

Change-Id: I632e4278aec4ee2d7373a6864d7d7c50fd067abc
Reviewed-on: https://gerrit.instructure.com/41052
Reviewed-by: Clay Diffrient <cdiffrient@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Ryan Shaw <ryan@instructure.com>
QA-Review: Ryan Shaw <ryan@instructure.com>