- Add AnnotationInstantiationMigrationProvider that augments loaded models...

- Add AnnotationInstantiationMigrationProvider that augments loaded models with annotations that have been added to the AF3 installation after the creation of the model.
- Note that:
  - It is still required to use AnnotationUtils.getAnnotation() to obtain (and potentially instantiate) an annotation. This is because annotations are only instantiated for newly added model elements if the annotation view is visible.
  - IMigrationProviders that convert old attribute values into annotations cannot rely on the fact that the annotation instance already exists (since the execution order of the IMigrationProviders is not defined). Hence, the need to use AnnotationUtils.getAnnotation(modelElement, clazz, false) to obtain (and potentially instantiate) an annotation (without wrapping the model access into a command, see #2010).
refs 1841