GitLab

* Removed enterprise enrollment element from the login elements
* Removed Gaia password changed, Supervision transition, Active Directory
password change screens from the oobe screens.
* Removed oobe-screen.{html,js} files as obsolete

Change-Id: I59c1bbc88b0233aba5c3f64e9d25cce053c538b8
Bug: 1084940
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2167271Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Commit-Queue: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771767}