Added item table settings overlay

__Tasks:__

- [x] gather feedback for my changes

Related PR: https://github.com/sulu-cmf/SuluSalesOrderBundle/pull/28

__Informations:__

| Q             | A
| ------------- | ---
| Tests pass?   | ???
| Fixed tickets | none
| BC Breaks     | none
| Doc           | none
@turbo-ele fixed