Stunner - Users do not understand how to add nodes to the diagram

When running the case management workshop, users are unable to add nodes the process diagram. In both the legacy editor and in Stunner, they do not understand that you need to drag the components onto the canvas. Some users click and then click on the canvas, while others can't even find where, for example, the script task is.

Acceptance Criteria
No default start node on new canvas.
Default empty state (canvas doesn't contain any node) shown without prompt to drag node from palette to canvas. The empty state reappears if the user deletes all nodes from the canvas.
Empty state is hidden when a user adds a node to the canvas. Hiding the empty state is triggered when the user releases the mouse button after clicking or dragging a node to the canvas.
When node is first added to the canvas, it is selected by default.
Expected also specific empty states UI for different domains (BPMN, DMN)
All points mentioned above are implemented as per Marvel Prototype
Tooltips have been moved to RHPAM-2520