Invalid shapes of newly created elements

[Shamann]

A shape of newly created elements is not modified upon shape switching. Reproduced on d5385ec

[Mvwivs]

Currently elements created from Stencil are only added to x6 graph. To allow layout calculations/view swithing elements should be added to application state (in this case sh:Shape and sh:Property collection), then state updates are propogated to Canvas, nodes and so on.
Adding nodes to state requires API from Mobx State Tree (@agentlab/sparql-jsld-client), this in turn requires "View" / "View kind" separation implementation #1