feat(rule-tester): fuzzy test for equality of moddle elements

[philippfromme]

Takes into account that reports might include instances of Base. Instances are replaced by ID or type allowing for tests like the following:

RuleTester.verify('foo', rule, {
  [],
  [
    {
      moddleElement: ...,
      report: {
        id: 'Task_1'
        message: 'Foo',
        node: 'Task_1' // instance replaced by ID
      }
    }
  ]
});