Allow other plugins to provide plugin data too

The filter should return an array, this could be an empty array or an array containing as a minimum the below for each plugin, obviously with data for the provides/depends key where applicable:
```php
array(
	'plugin-dir/file.php' => array(
		'Name' => 'Plugin name',
		'Provides' => '',
		'Depends' => '',
	)
)
```
@jrfnl I think these `if` conditionals can be removed. For one, an empty array will just be skipped over by `foreach`. And then above when you do:

```
$arrays = func_get_args();
```

You can then do:

```
if ( count( $arrays ) !== count( array_map( 'is_array', $arrays ) ) ) {
    return array(); // or some error state
}
```