Change LogEventsList to use query info from DatabaseLogEntry.

Change LogEventsList to use query info from DatabaseLogEntry.
The only changes in the query are:
* New fields: log_user_text, user_id
* INNER JOIN on user table is changed to LEFT JOIN
* AND (user_id = log_user) is dropped from WHERE conditions (looks redundant, easy to add back if needed)

This means that log entries from anonymous users are not dropped anymore.
Those will actually get displayed correctly after the next commit.
It is also possible to use User::newFromRow for non-anonymous users now.