Enable a Constraint Severity of WARNING vs. ERROR

[cchouina]

Checked for duplicates

Yes - I've already checked

Alternatives considered

Yes - and alternatives don't suffice

Related problems

Related idea: #975

Describe the feature request

I would like to be able to write a Constraint-style formulaic set of Rules using one interface yet only apply a WARNING severity of the "Constraint" Rule vs. an ERROR severity. A "Warning Checker" and a "Constraint Checker" in one.