Improve logging

[keeloo]

Organise logging in such a way that it becomes more usable. At the
moment, non-critical errors accumulate, causing the log file to be
very large. As a result, the log file cannot be mailed, making it more
difficult to monitor the ingestion process. Therefore, find a way to
'compress' errors of the same kind into one. The change needed can be
considered major because without it, the analyses of problems becomes
more and more difficult.

[keeloo]

Sorry, wrong component. Testing if I get a mail as a result of a change.

[keeloo]

Instead of having the log file mailed, connect to the new logging framework.