Add more --debug logging to CLI for http-retries

[JonJagger]

swedbank had an issue where more detailed CLI logging of the individual http-retry failures might have been useful.

The issue turned out to be that when they tried the kosli-attest-artifact command it worked.
But when they tried the kosli-attest-junit it did not work.
The former was using the ubuntu-latest runner and the latter was using a custom-runner.
They thought they had opened the firewall for the custom-runner but they hadn't.

There is a CLI branch + PR that may help address this
by printing each individual http request (when there are retries) if you have set the --debug flag.
See #397

With some effort we could reproduce this scenario so we can see what actual error message the
http request returns when you get these firewall problems.

[JonJagger]

Steve had some good findings in these slack comments
https://kosli-internal.slack.com/archives/C01UMS1CEN5/p1736850236586739
https://kosli-internal.slack.com/archives/C01UMS1CEN5/p1736850601221539