Refactor IDocumentSettingAccess Interface of SwDoc

Change-Id: I4a7ec73d3bdf9888e50d071b593798b74780b80c
Split out the IDocumentDeviceAccess interface of SwDoc.

The interface implementation is now in the class DocumentDeviceManager and
SwDoc has a member variable of that class to which the Interface's
method calls get forwarded.
The following methods were also moved because they are only used by this
interface:
CreateVirtualDevice_, CreatePrinter_ and PrtDataChanged.

Change-Id: I0b0de6540f0c8635ce560381fb924a3d9cd50c0e