[REQ][JAVA] Add JsonIgnoreProperties to model

Administrator
2023-03-19T17:15:31Z

*Created by: Fjolnir-Dvorak*

Work in progress. I only did the Pojo class so far. Enums and other specialities have to be checked, too.

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### Description of the PR

Added the annotation
```java
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@JsonIgnoreProperties(ignoreUnknown = true)
```
to every generated Pojo. This feature can be turned off via the flag `disableAdditionalFieldsAnnotation`.
This makes the generated code more independend from the attached default json parser.

### Fixed Issues:
- fixes https://github.com/OpenAPITools/openapi-generator/issues/3438

### Technical Commitee for Java:
@bbdouglas (2017/07) @sreeshas (2017/08) @jfiala (2017/08) @lukoyanov (2017/09) @cbornet (2017/09) @jeff9finger (2018/01) @karismann (2019/03) @Zomzog (2019/04)