Fixed various issues and implemented some new features around the new ScanningQueryEngine

This PR contains different commits related to different query-related issues, as follows:
* MODE-2178 - fixed the code for various types of JOINS and also shareable nodes. Enabled back all the previously disabled Tck tests
* MODE-2247 - implemented the `INTERSECT` and `EXCEPT` operations together with several new test cases
* MODE-2209 - implemented the ability to check `READ` permissions for nodes returned from a query, via a new `NodeSequence` implementation
The `contains` method really does the same thing as the `add` method, so do we really need both? Perhaps `addIfAbsent` is a better name; I was trying to keep it short, but perhaps `contains` is too unnatural in some cases.