* Add Start/End subquery node skeleton
* Added a test query that triggers complex interna in the future and needs to proof that our work is side-effect free.
* Add template function to statically assert size of type
* Add Start/End subquery node skeleton
* Add Start/End subquery node creation to ExecutionNode
* Cleanup SubqueryEndNode
* Add test file
* Add isEqualTo to ExecutionNode
* Subquery nodes cleanup
* Update ExecutionNode tests
* Updates to testing code
* More updates
* Add optimizer rule
* Fix optimizer rule
* Fix optimizer rule (again)
* Add a public function to get plan from query
* Fix register planning
* Add test for splicing subquery nodes
* add static asserts for sizes of SubqueryStartNode and SubqueryEndNode
* Add comment about statically asserted size
* Fix isEqualTo virtual and override dance.
* Fix isEqualTo, remove static_assert_size
* Remove a TODO; the plan owns the ExecutionNodes
* Only add stealPlan to Query when testing
* Remove another static_assert_size
* Disabled subquery splice rule by default
* temporarily modified test
* Fixed windows compile
* Fixed unused variable warning