remove author headers from source files

these comments are obsolet on the class level:

```java
/**
* @author xy
*/
```

git history already provides this information.

**acceptance criteria**: remove the `@author` comments from the top of all source files.

Search the repository's source files for class-level comments containing @author, starting with the Java source tree. Remove those author comments from all source files, then repeat the search to verify that no such comments remain.

Written by the indexing model from the issue text.