This leaves the user record and host records in the DB
to avoid dangling references from the result table.
It:
- changes the user name, email addr, and auth to "deleted_xxx"
- removes the user from team
- removes posts by the user
- removes PMs by the user
- removes friend connection
- removes profile
- "anonymizes" the hosts (erase IP addr and domain name)
Note 1: this is accessed by admins using a script in ops/;
It's not available to users.
Note 2: this may not satisfy the requirements of EU-GDPR
since it doesn't delete the user and host records.