Implement Requirement 6: No redirects

[oxisto]

This is actually just a recommendation and if we have to see whether we even have access to the original headers in a redirect or if we can configure ktor in a way that ignores redirect and thus this requirement is "always true".

See https://docs.oasis-open.org/csaf/csaf/v2.0/os/csaf-v2.0-os.html#716-requirement-6-no-redirects