Spam reporting patch (#9)

Spam reporting patch

Spam reporting is available for trusted users (org members) via a button on a
spammer's profile page;
processing is done automatically using a new cron task process_spam_reports;
a new section Site Administration > Identity & Access > Spam Reports.

See #7 for the code review.

---------

Co-authored-by: Oleg Komarov <[email protected]>

Author: komarov