Removing ApiWrapper and adding sinon (#11340)

* Added sinon
removed api wrapper
removed unnecesaary utils

* merged from testfix

* merged from aasim/import/downloadTestFix

* merge from aasim/import/downloadTestFix

extensions/import/package.json

@@ -73,10 +73,12 @@
 	"devDependencies": {
     "@types/mocha": "^5.2.5",
     "@types/node": "^12.11.7",
+    "@types/sinon": "^9.0.4",
     "mocha": "^5.2.0",
     "mocha-junit-reporter": "^1.17.0",
     "mocha-multi-reporters": "^1.1.7",
     "should": "^13.2.1",
+    "sinon": "^9.0.2",
     "typemoq": "^2.1.0",
     "vscodetestcover": "^1.0.9"
 	},