Adapts Exception Handler to conform standard

[FriedJannik]

Description of Changes

This PR adapts the error handling to return meaningful messages in a standardised format.

Now each Error resulting from a request by the user should provide a meaningful and standardized error message:

[
    {
        "code": 400,
        "messageType": "Error",
        "correlationId": "MethodArgumentTypeMismatchException-400",
        "text": "Method parameter 'aasIdentifier': Failed to convert value of type 'java.lang.String' to required type 'org.eclipse.digitaltwin.basyx.http.Base64UrlEncodedIdentifier'; Failed to convert from type [java.lang.String] to type [@io.swagger.v3.oas.annotations.Parameter @org.springframework.web.bind.annotation.PathVariable org.eclipse.digitaltwin.basyx.http.Base64UrlEncodedIdentifier] for value [2]",
        "timestamp": "2025-05-07T06:49:08.352062600Z"
    }
]

Please note that timestamps are always provided in UTC ISO 8601.
The Correlation ID is always formed of the Exception Name and the Error Code, ensuring uniqueness.

Related Issue

#519

BaSyx Configuration for Testing

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AAS Files Used for Testing

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Additional Information

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[FriedJannik]

Note: MongoQueryException (Unathorized) also returns 500