[luci][realms] configure LUCI realms.

Motivation: this is a migration to more hardened security ACLs inside
LUCI. Most notably, the end goal is better isolation between projects
using LUCI.

R=ngeoffray

Bug: chromium:1232009
Bug: https://crbug.com/1232009
Change-Id: Ie680943ab0ab380c458cf951cc8a4c761e9506c9
4 files changed