Allow multiple site profile support

@scalvert @kbingman 

We need to have the ability to support multiple site profiles. Localization is a good example of this usage.

Note: This does require updates to nightwatch-generator

The proposed new site.json should structure like the following:
```
{
  "activeProfile": "default",
  "profiles": {
    "default": {
      "bundleUrl": "http://localhost:8080",
      "siteUrl": "http://www.yoursite.com"
    }
  }
}
```

An example of the use of this new structure:
```
{
  "activeProfile": "UK",
  "profiles": {
    "US": {
      "bundleUrl": "http://localhost:8080",
	  "siteUrl": "https://buy.garmin.com/en-US/US/index.ep"
    },
    "UK": {
   	  "bundleUrl": "http://localhost:8080",
	  "siteUrl": "https://buy.garmin.com/en-GB/GB/index.ep"
    },
    "DE": {
   	  "bundleUrl": "http://localhost:8080",
	  "siteUrl": "https://buy.garmin.com/de-DE/DE/index.ep"
    },
    "FR": {
   	  "bundleUrl": "http://localhost:8080",
	  "siteUrl": "https://buy.garmin.com/fr-FR/FR/index.ep"
    }
  }
}
```