Bundle configuration normalization error fixed

Xml pluralization is not needed as `default_domain` is now a scalar node instead of an array.

Having it will throw an InvalidConfigurationException (only if value is configured)

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I didn't want to open a new issue for this but I'm wondering: 
Why rename the bundle instead of creating another repo? I don't want to sound critical or anything but wouldn't this have given others more time to update their applications accordingly?