Add Sirius-based validation framework

[paulgaspardo]

This adds a new model validation framework to Rosetta where constraints are implemented as methods in classes registered as Java Extensions in a Sirius viewpoint, including:

• ValidationService, an abstract base class for all classes implementing validation constraints to manage registration and reflectively loading constraint methods.
• OmlValidationService, a ValiationService subclass which adds parameter annotations to allow filtering by OML types.
• ValidateLineHandler, which adds a menu item allowing users to invoke validation constraints from Sirius tables.
• MarkerRepresentationElementSelector, an IGotoMarker implementation that works with ValidateLineHandler to allow users to double-click errors in the problems view to go to the error location in Sirius.