Adds Middleware API (#40)

* Adds test project

* Adds e2e for end-2-end tests

* Update gitignore

* Update loaders

* Creates test project

* v0.1.27

* Upgrade

* dependency fixes

* Load project plugins in the plugin loader

* Issue with instanceof

* Fixes versioning issues

* Adds medusa middleware api

* Adds documentation

* Fixes tests

e2e/prod-project/.prettierrc

@@ -0,0 +1,8 @@
+{
+  "endOfLine": "lf",
+  "semi": false,
+  "singleQuote": false,
+  "tabWidth": 2,
+  "trailingComma": "es5"
+}
+