Added Vagrant configuration cookbook

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes
| Applies to    | all
| Fixed tickets | n/a

A new cookbook article was added with an example Vagrant configuration that can be used with the Symfony Standard Edition.
Once the configuration content has been copied/pasted into a new file, the developer should be able to customize the configuration however they want.  For this basic configuration, it really didn't need that additional complexity.