The XDocuments representing the DOM documents of a
DrawingML diagram (Smart-Art) are now stored as
the PropertyValues "OOXData", "OOXLayout",
"OOXStyle",  "OOXColor" and "OOXDrawing" into the
"InteropGraBag" property of the parent
SvxGroupShape created from such diagram.

Modified the oox::drawingml::dgm::Diagram class to
be able to hold the map storing the XDocuments and
its names. Added the getDomMap() method to obtain
the map directly and the getDomsAsPropertyValues
method to get the map as a sequence of Property
Values.

Modified the methods for importing and loading the
Smart-Art into the Diagram so they add
automatically the DOM documents to it.

Modified the oox::drawingml::Shape class to be
able to hold the sequence of PropertyValues
storing the XDocuments and its names coming from
the oox::drawingml::dgm::Diagram class. Added the
getDiagramDoms() and setDiagramDoms() methods.

Enhanced the
oox::shape::ShapeContextHandler::getShape() method
to add the extended drawing document to the
oox::drawingml::Shape class.

Modified the
oox::drawingml::Shape::createAndInsert() method to
store the sequence of XDocuments in the
"InteropGrabBag" property of the GroupShape
service SvxGroupShape implementation representing
a Smart-Art.

Change-Id: I7d0b9dfbfc9d5299ddd25fab394e5e9a422d1dd1
Reviewed-on: https://gerrit.libreoffice.org/5849Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>