Add the ability to auto-prune logged IPs etc.

At the moment IP of users, who wrote a posts or got an log-entry in the ACP a getting stored endless.

Which leads to >10 years old information to IPs. This is a little waste of space, because a too old IP won't help anyone.

At the other hand, this can lead to problems with eh privacy policy in some countries, e.g. Germany.

So an option in the ACP would be nice, which allows:

• don't store IP adresses at all
• store, but
  • remove them never
  • remove them after x years, months, weeks, days