Expose audit log over xml rpc interface

[plajjan]

We keep an audit log today for all changes but the log is not accessible via the xml rpc api... Fix that!

Should there be one function for fetching audit information or should there be one per object type?

Including audit information in the result of a list function would likely result in a huge result and is therefore not practical. One approach would be to have a get_prefix function or similar which could be used to fetch all information on a prefix, including the audit log. While it does have its benefits, like also being able to include future statistical information, it does not allow for searching the audit log.

Do we need multiple functions to fetch the data?

[plajjan]

I think the get_prefix function would be a good idea. It could also serve to return statistics on the prefix and similar data.