* use `csaf_distribution` with an underscore as underscores
are allowed by RFC9110 and it is more consistent as it is used
with underscore at other places.
* change example to `VERSION` to indicate that this is dynamic.
* Remove verbose flag from downloader.
* Do structured http logging in forwarder, too.
* Use structured logging to separate http traffic of downloader from forwarder.
* Implement a logging client and activate it using verbose parameter or option
in checker and aggregator.
Co-authored-by: Sascha L. Teichmann <sascha.teichmann@intevation.de>
