* convert system database references from SSDT
* remove empty ItemGroup if no other database references
* fix baseline files
* also update sqlproj if system database references were added in SSDT since the sqlproj got updated with ADS imports
* undo change
* move updating system db references out of updateProjectForRoundTrip()
* update test to have an already updated system db ref
* add clean target after merge from master
* add await
* addressing comments
* Test code for round tripping feature
* Fixed tests. Edited updateImportedTargetsToProjFile method to push newly added import target to the list.
* Added couple more tests
* Addressed comment
