[EEF] Create a new installable unit dedicated to UML EEF Properties

Description

The purpose of this task is to allow to the user to install only the UML EEF Properties, without installing the Sirius Diagram.

We will split the file org.eclipse.papyrus.sirius.uml.diagram.architecture/§resource/sirius-diagram.Architecture in 2 files :

the same as today, without the EEF contribution
a new one, with only the EEF contribution, in a new plugin called org.eclipse.papyrus.sirius.properties.uml.architecture

the new plugin org.eclipse.papyrus.sirius.properties.uml.architecture must be contributed into the existing feature oep.sirius.properties.feature

Then, in the category.xml file, we will create a new category called
Papyrus-EEF Properties. Thi scategory will provide the properties features.

At the end of the process, we should be able to install only the EEF plugin :-).