Configuration panel for referral policy

[uazo]

Description

I modified the patch to add a configuration panel:

the options, as we said, become three:

texts may be incorrect, feel free of course to modify them as you see fit.

fixes #2397

All submissions

• there are no other open Pull Requests for the same update/change
• Bromite can be built with these changes
• I have tested that the new change works as intended (AVD or physical device will do)

Format

• patch subject and filename match (e.g. Subject: Alternative cache (NIK-based) -> Alternative-cache-NIK-based.patch)
• patch description contains explanation of changes
• no unnecessary whitespace or unrelated changes