fix json schema urls

• Fix XSD Konverter attributes (according to the spec here: https://gitlab.opencode.de/fitko/fim/schema-repository/uploads/6ac48a26fa3a98f16d0c79b2f1c425a1/XSLT-Test-v20-20230606_151147.pdf, and the example data in the original ticket #168 (closed))
• Clean up XSD Konverter error handling
• Create a canonical_hash of the json schema content with a fixed IDs for change detection
• Only update, when this ID has changed
• pass the baseurl via the config to generate the correct json schema id

The Service class now has an additional dependency on the baseurl, which is a little ugly, and we should probably introduce a RuntimeConfig or something similar to bundle the values in the future when there are additional dependencies. But for now, I thought this is still got enough.