lets pass in a useful error message to all ConstraintViolationException() exceptions

[jstrachan]

I just hit some validation exceptions in fmp and the error message was literally just ConstraintViolationException. No clue as to what validation failed where or why.

It looks like there's no validation message by default. Details of the workaround in fmp here:
fabric8io/fabric8-maven-plugin#711

I've patched fmp to add a this constructor argument; it'd be nice to do this in a helper method inside kubernetes-model so all throws have a nice useful message of what validation failed and why.

e.g. so lets use a helper function to create a ConstraintViolationException object which we can then generate a nice message like this code:
fabric8io/fabric8-maven-plugin@4de0bdf#diff-00c124578b1d9f956274da34bb5c3641R448

[jstrachan]

e.g. the generated code is

    private <T>void validate(T item){
            if (!validationEnabled) { return; }
            Validator validator = null;
            try {
                ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
                validator = factory.getValidator();
            } catch(ValidationException e) {return;}
            Set<ConstraintViolation<T>> violations = validator.validate(item);
            if (!violations.isEmpty()) {
            throw new ConstraintViolationException(violations);
             }
    }

lets try pass in an extra String message to that last throw statement

[jimmidyson]

This is generated by sundrio so needs to be fixed there rather than here, which just uses sundrio to generate the builders.