ModuleManager load module childs dependents

Allow load modules (from ```Module::init()```) after current module.
Analog of https://github.com/zendframework/zf2/pull/5651, but:
   load modules ```A, B``` - configs order is ```A, B```.
   load modules ```A -> B``` - configs order is ```A, B```.
`= null` is implicit, no need to define it