Feature/graph insights doc v19.2.0

[MaximilianWenzel]

Documentation Updates (v19.2.0)

• User Guide: Updated to v19.2.0, including new screenshots for the latest UI functionality.
• Graph Insights cover: Replaced the vulnerability dataset image graph-insights-explore.png.
  • Note: If you prefer to revert to the vulnerability dataset, I would recommend using a new screenshot with the latest version. The old one is outdated since the database summary is now searchable.

Technical Issue: IRI Length Limits in northwind-data.ttl
We've run into an issue with the images included in the northwind-data.ttl file (appearing under [No class] in the class tree).
Currently, the image payloads are encoded directly in the IRI (e.g., data:image/png;base64,iVBORw0KGgo...).

• Symptom: Because these IRIs are used as Base64-encoded parameters in our routes, the string lengths exceed the URI capacity of the reverse proxy and our Spring backend - a click on one of the resources results in an exception.
• Resolution: We require consistent IRI IDs across versions for UI deep links and our routes. Since we do not plan to process binary data from IRIs, we might prune them in the future to avoid this issue (e.g. <PRUNED-SUBSTRING>-<LENGTH>-<HASH>).