Remove MONGOLAB_URI and mlab connection string

* MONGOLAB_URI isn't needed as the mongolab addon has been removed
* Removed the old mlab connection URI as that database will be deleted
* Default db is localhost:27017, for all other cases set MONGODB_URI
  (don't commit database credentials to a public repo)

config/env/all.js

@@ -1,11 +1,7 @@
 // default app configuration
 
 const port = process.env.PORT || 4000;
-let db = process.env.MONGOLAB_URI || process.env.MONGODB_URI;
-
-if (!db) {
-  db = process.env.NODE_ENV === 'test' ? "mongodb://localhost:27017/nodegoat" : "mongodb://nodegoat:owasp@ds159217.mlab.com:59217/nodegoat";
-}
+let db = process.env.MONGODB_URI || "mongodb://localhost:27017/nodegoat";
 
 module.exports = {
     port,

config/env/development.js

@@ -1,16 +1,4 @@
 module.exports = {
-   // Local instance.
-   // To install mongodb: https://docs.mongodb.org/manual/tutorial/
-   // With mongodb installed, All you should need to do is uncomment the `db` property below, and run the following command:
-   // grunt db-reset:development
-   // That will create the local nodegoat data-store, or restore it to a clean state if it already exists.
-
-   // db: "mongodb://localhost:27017/nodegoat",
-
-   // If you want to use a MongoLab instance, just sign up for it, create a data-store, in this example we call it nodegoat.
-   // and again just run the grunt db-reset:development command
-   //db: 'mongodb://<dbuser>:<dbpassword>@<databasename>',
-
    // If you want to debug regression tests, you will need the following which is also in the test config:
    zapHostName: "192.168.56.20",
    zapPort: "8080",