Add Sirius Specification Environment into the Capella Studio bundle

[arnauddieumegard]

Sirius Specification Environment (org.eclipse.sirius.specifier.feature) is not included in Capella Studio. I t may be good to add it to access its features in the odesign files properties view.

Need to ensure that features/attributes set through the contributed editor are handled when deploying them in a Capella viewpoint.

https://www.eclipse.org/forums/index.php/t/1110554/

https://forum.mbse-capella.org/t/using-sirius-specifier-properties-view-with-capella-model-issue/5365/4

[arnauddieumegard]

In addition to the related fix, for the generated viewpoints to be able to contribute such extensions to Capella, one may need to add runtime features for eef and sirius specifier properties to Capella or to include them in the bundled viewpoint.

<includes id="org.eclipse.sirius.runtime.ide.eef" version="0.0.0"/>
<includes id="org.eclipse.sirius.properties.feature" version="0.0.0"/>
<includes id="org.eclipse.eef.ext.widgets.reference.feature" version="0.0.0"/>
<includes id="org.eclipse.eef.sdk.feature" version="0.0.0"/>

Documentation on viewpoints has been updated: https://github.com/eclipse/capella/wiki/Viewpoint-Development#sirius-property-views

[arnauddieumegard]

As stated in https://github.com/eclipse/capella/wiki/Viewpoint-Development#sirius-property-views, adding the required sirius and eef features may cause issues or incompatibilities on the Capella side. Thus creating a viewpoint using this feature is not officially supported and shall be done knowing that issues may happen.