Extend rule capabilities in domain blacklist #257
Description
Continuing from openrightsgroup/blocked-org-uk#402
We could also extend the domain blacklist feature to support exclusions to the broader patterns. For instance:
.*porn is a pattern blocked by the submission filter, but (for example), .*factsboutporn (a hypothetical public information site) might be something that should be submittable.
The submission filter could be modified to accept allow rules, which would override a broader deny rule.