Add a parameter to allow a host for entities

This will help to test sites that are currently blocked.

This is part of a 3 part change:
=> crrev.com/c/6239855 : add a force allow parameter
 - crrev.com/i/8010568 : fix tests
 - crrev.com/c/6234587 : block IP addresses

Change-Id: I587e4eee9f540e93f801b62246bca08baf8b03df
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6239855
Reviewed-by: Raj T <rajendrant@chromium.org>
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1417212}