Use kotlin-logging

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We are using the logging framework pretty "java style", which means when adding debug or trace logs, we need to do tedious stuff like

if (log.isTraceEnabled()) {
            log.trace("Some log message that probably never appears anywhere")
}

This is 3 lines of code for something you probably only need once when you debug a new feature.

This can be done much easier and prettier with https://github.com/MicroUtils/kotlin-logging

So in this issue we should

• Use kotlin-logging as dependency (we will still need the sl4j-classic dependency)
• Update all usages of LoggerFactory to more easily instantiate loggers
• Check for isXYEnabled calls to change them to log.trace { "whatever"}