Revert of [i18n] chromeos login i18n-content to $i18n{} (patchset #4 id:80001 of https://codereview…

Revert of [i18n] chromeos login i18n-content to $i18n{} (patchset #4 id:80001 of https://codereview.chromium.org/2626123002/ )

Reason for revert:
crbug/691904 reports that when changing the language, the pages are not redrawn in the newly selected language. This CL is not critical to get into M-57 so I'm reverting it to get a M-57 working asap. I can look into it further for a later milestone.

Original issue's description:
> [i18n] chromeos login i18n-content to $i18n{}
>
> This is a semi-mechanical change to convert i18n-content to $i18n{}. The
> Non-mechancal changes are some formatting adjustments.
>
> BUG=677338
> CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
>
> Review-Url: https://codereview.chromium.org/2626123002
> Cr-Commit-Position: refs/heads/master@{#443327}
> Committed: https://chromium.googlesource.com/chromium/src/+/9dfcececdc896dd4be4d516de61d7f8bceebea99

TBR=tommycli@chromium.org
BUG=691904
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2694353002
Cr-Commit-Position: refs/heads/master@{#450762}
(cherry picked from commit 8f21fb41278cc936a74fa33148ca01d394dd54a9)