Add a debug mode for diagrams

[sbegaudeau]

Using a field like DiagramDescription#debug, we should be able to activate a debug mode for a diagram. In the debug mode, the frontend should display positions, sizes for all the relevant elements.

This will make it easier to debug the layout of the diagrams.

[sbegaudeau]

• In diagram.graphqls, a new field debug: Boolean on DiagramDescription
• DiagramDescriptionDebugDataFetcher which should return true if we have a configuration property sirius.components.diagram.debug=true
• In DiagramRepresentation, you should retrieve the value of debug when we are retrieving the diagram description (see the getDiagramDescriptionQuery and its types)
• In convertDiagram.ts, you should add a debug property to Diagram (and its type too)
• In RectangleView.tsx, detect if debug is true (try to retrieve the diagram from a node and check the value of debug)
• If it is true, display the position { x: 285.99, y: 317.343 } in the top left corner of the node, then display the width: 2343 on the bottom and height:343 on the left