optimize content ratings in app resource (bug 948192)

Rather than having in the app resource:

```
'ratings': {
    'us': <ESRB_RATING>,
    've': <ESRB_RATING>,
    'mx': <ESRB_RATING>,
    'sp': <PEGI_RATING>,
    'it': <PEGI_RATING>
}
```

Remove redundancy and refactor to:

```
'content_ratings': {
    'regions': {
        'us': 'esrb',
        've': 'esrb',
        'mx': 'esrb',
        'sp': 'pegi',
        'it': 'pegi',
        ...  
    },
    'ratings': {
        'esrb': <ESRB_RATING>,
        'pegi': <PEGI_RATING>,
        'generic': <GENERIC_RATING> 
    }
}
```
Greatly reducing the size of the app resource to Fireplace.

Fireplace/Flue being updated.