reworking decomposition mechanism

...ortiss/tooling/base/ui/action/CutModelElementsAction.java

...ng/base/ui/compose/ConnectorConnectionCompositorBase.java

...ui/compose/HierarchicElementConnectionCompositorBase.java

...tooling/base/ui/editor/gef/GraphicalViewerEditorBase.java

...iss/tooling/base/ui/editpart/policy/RemoveEditPolicy.java

...oling/base/decompose/HierarchicElementCompositorBase.java

...iss/tooling/base/decompose/IConnectionCompositorBase.java

...org/fortiss/tooling/kernel/ui/internal/ActionService.java

.../tooling/kernel/internal/ConnectionCompositorService.java

...iss/tooling/kernel/internal/ElementCompositorService.java

.../tooling/kernel/service/IConnectionCompositorService.java

...iss/tooling/kernel/service/IElementCompositorService.java