Fix File Encoding Issues when writing java files

[tcmj]

• clean utf-8 support and
• ability to change the encoding
• due to platform needs

-default to utf-8
-ability to change it with the standard maven property ?
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

[tcmj]

Priority: Minor
Todo: find concrete issues
Atm everything should be bound to UTF-8 which should be fine

[tcmj]

added a new property to our maven mojo

 @Parameter(defaultValue = "${project.build.sourceEncoding}", required = true, readonly = true)
  private String encoding;

[tcmj]

Additionally we can see the encoding used in the info log message:
[INFO] * * SourceOutputDirectory: 'D:\gitwork\workspace-tcmj-iso\tcmj-pug-enums\examples-api\src\main\generated', OutputEncoding: UTF-8 * *