Offer Windows Group Policy templates for automatic updates

[mherrmann]

Brave supports similar group policy settings (modulo some registry paths) as Chrome for automatic updates. For example, automatic updates can be globally switched off with such a setting. Or they can be restricted by sysadmins to known-to-be-good version numbers. The goal of this issue is to offer Group Policy templates for Brave that are similar to those offered by Google. Brave's templates can likely be offered in the same place as #26501.