Make SysML validation more modular

[flatombe]

Currently the SysML validation rules are defined in org.eclipse.syson.sysml.validation.SysMLv2ValidationRules and called through org.eclipse.syson.sysml.validation.SysMLv2Validator by org.eclipse.syson.sysml.validation.SysMLv2ValidationService.

All possible rules are always executed when possible, which in practice is a problem for SysON and downstream applications:

• Some rules do not execute correctly, e.g. A warning has occurred with the expression 'aql:self.owningType <> null and not self.owningFeatureMembership.oclIsKindOf(sysml::ReturnParameterMembership) and (self.owningType.oclIsKindOf(sysml::Behavior) or self.owningType.oclIsKindOf(sysml::Step) and (self.owningType.oclIsKindOf(sysml::InvocationExpression) implies not self.ownedRedefinition->exists(e | not e.isImplied)) implies let i : Integer = self.owningType.ownedFeature->select(f | f.direction <> null)->reject(i | i.owningFeatureMembership.oclIsKindOf(sysml::ReturnParameterMembership))->indexOf(self) in self.owningType.ownedSpecialization.general->forAll(supertype | let ownedParameters : Sequence(sysml::Feature) = supertype.ownedFeature->select(f | f.direction <> null)->reject(i | i.owningFeatureMembership.oclIsKindOf(sysml::ReturnParameterMembership)) in ownedParameters->size() >= i implies self.redefines(ownedParameters->at(i)))': Couldn't find the 'redefines(EClassifier=ReferenceUsage,org.eclipse.acceleo.query.runtime.impl.Nothing)' service
• Some rules are not actionable because the issue lies in SysON (e.g. a missing a implicit FeatureTyping)

Ideally the validation rules should be unit-tested and their performance tested, to ensure downstream applications can use them safely on large models. However this represents a significant development effort.

As a first step in this direction, we will make which SysML validation rules are applied more modular, allowing downstream applications to configure which rules they wish to see applied.