Patch provides ability to control whether check MOJO violations cause build failure (inline with pmd:check)

Example:

mvn -Dcheckstyle.failOnViolation=false checkstyle:check

Use case:

In the same way that test failures can be prevented from failing the buyild via a CLI arg, builds that enforce governance standards and policies such as no checkstyle violations, no PMD violations, at least XX% of test coverage, no javadoc warnings are more useful if they can also be deactivated via a CLI arg.

Note, my previous PMD:check mojo patch already provides support for this violation override.