* Metamodel
  * Introduce dedicated container classes for constraints, events,
    timing chains to enable visualization based in kernel UI handlers
  * Add curresponding convenience eOperations in TimingSpecification
* Implement visualization for constraint container and period
  constraints
* Visualization for event chains prepared, but currently unused
* Visualization of events is currently not forseen (Events should be
  managed in the background)

Issue-Ref: 3470
Issue-Url: https://af3-developer.fortiss.org/issues/3470



Signed-off-by: Simon Barner <barner@fortiss.org>