Support structured options in @Commands

ver considered allowing something like

generateEntities(@Option String table, @Option String catalog, @Option @Option String schema, @NestedOption final JPADataSource datasource)

class DataSource {

public DataSource(@Option(...) String name, @Option(..) password, @Option(..) ..)

...
)

Which would actually provide some more nested structure and be useful in ui construction in IDE plus better naming of things even in shell ?

Would also be good to be able to reference "default" @JPADatasource should be "production", "dev" or "test" if SEAMFORGE-210 comes to life?