Creates test request helper for API endpoints

Separates common utils into the medusa-core-utils package.
Sets up a testing environment where mocked models/services/etc. can be placed in
__mocks__ folder within its corresponding directory. The mocks will
automatically be registered in a awilix container only used for testing.

packages/medusa/package.json

@@ -19,10 +19,12 @@
     "@babel/preset-env": "^7.7.5",
     "@babel/register": "^7.7.4",
     "@babel/runtime": "^7.7.6",
+    "client-sessions": "^0.8.0",
     "eslint": "^6.7.2",
     "jest": "^24.9.0",
     "nodemon": "^2.0.1",
-    "prettier": "^1.19.1"
+    "prettier": "^1.19.1",
+    "supertest": "^4.0.2"
   },
   "scripts": {
     "start": "nodemon --watch plugins/ --watch src/ --exec babel-node src/app.js",
@@ -42,13 +44,15 @@
     "dotenv": "^8.2.0",
     "express": "^4.17.1",
     "express-session": "^1.17.0",
-    "joi-objectid": "^3.0.1",
     "fs-exists-cached": "^1.0.0",
     "glob": "^7.1.6",
+    "joi-objectid": "^3.0.1",
     "jsonwebtoken": "^8.5.1",
+    "medusa-core-utils": "^1.0.0",
     "mongoose": "^5.8.0",
     "morgan": "^1.9.1",
     "passport": "^0.4.0",
+    "passport-http-bearer": "^1.0.1",
     "passport-jwt": "^4.0.0",
     "passport-local": "^1.0.0",
     "regenerator-runtime": "^0.13.3",