[SplitSettings] Add Kerberos account UI for OS settings

This cherry-picks the relevant changes from
https://chromium-review.googlesource.com/c/chromium/src/+/1584270/

BUG=950007

Change-Id: I8dd900e701ff0d867bb8f4751cc11a91713abdaf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1600434
Commit-Queue: May Lippert <maybelle@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Lutz Justen <ljusten@chromium.org>
Auto-Submit: May Lippert <maybelle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661479}
7 files changed