Added $filters to AAS QL & enhanced Fragment Fieldidentifiers

[Martin187187]

• implements Add optional FILTER to Query #517
• added new Query Language Filter chapter in Query Language chapter.
• Enhanced the FieldIdentifier Fragment Definition from just plain string to a BNF specification. => allow non leaf paths and disallow required paths.
• updated Json schema & api accordingly.
• Addition does not introduce breaking changes because it only adds new optional field
• allow multiple filters instead of just 1 in the current security specification

[CLAassistant]

All committers have signed the CLA.

[Martin187187]

Hi @Martin187187 ,

thanks a lot for this pull request.

I have reviewed this PR and provided the following review remarks mainly for naming inconsistency. Please note that the naming inconsistency might not be limited to what I pointed out, so please check other files and locations.

Thanks alot for your review @mdanish98. I fixed the naming inconsistencies.

[Martin187187]

I changed a lot here because:

• added Fragment Field Identifier that are used to express what to filter (different to normal field identifier
• I noticed huge gaps between the json and bnf. I fixed the inconsistencies in the BNF so JSON schema has no breaking changes

[Martin187187]

I’ve updated this PR after identifying several inconsistencies and gaps between the JSON Schema and the BNF.

Specifically:

• Aligned the BNF with the JSON Schema to ensure consistent terminology (e.g., avoiding different keywords for the same concept).
• Improved and clarified the required logic in the JSON Schema.
• Verified the updated schema against existing access rules and queries currently used in BaSyx to ensure compatibility and correctness.

If you’d like to review the test cases or see how I validated the schema, you can find them here:
https://github.com/Martin187187/basyx-go-components/tree/json-schema-tests/internal/common/security/schema_tests

Happy to provide additional test data or walk through the validation approach if needed.

[Martin187187]

There was a significant discrepancy between the security JSON schema and the API JSON schema. In the security specification, the fragment object is nested inside the filter object, but this is not the case in the API schema. I have now updated both documents to use the security version for consistency.

[Martin187187]

blocked by #548