Move system_settings_provider into chromeos/system

Moves system_settings_provider from chrome/browser/chromeos/system to
chromeos/system - part of an effort to move cros_settings and related
settings code out of chrome/browser and into chromeos/system, so that
they can be used in processes other than the chrome process.

Duplicates the timezone_util functions that system_settings_provider
depends on - ideally, all of timezone_util would move too but since
it depends on cros_settings, it might have to be moved last.

Bug: 446937
Change-Id: I3863cd3dd274b0f94dc4d87938b7ccda2fe89269
Reviewed-on: https://chromium-review.googlesource.com/c/1128861
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Lutz Justen <ljusten@chromium.org>
Commit-Queue: A Olsen <olsen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596559}
5 files changed