Added support for the Roaming Profile Location upstream Chromium management policy.

mindst you linked to a different policy than what was mentioned in the release notes; I assume you meant to paste this one:  https://cloud.google.com/docs/chrome-enterprise/policies/?policy=RoamingProfileLocation.  Looking back on it, I don't think I actually should have mentioned this in here.  Our intention with enabling support for this policy was that it would be part of our broader work to support syncing for on-prem accounts, but that work isn't done yet.  Nor, for that matter, is our ability to support roaming profile data in general, which makes this particular policy, on its own, pretty useless.