Namespace collision with migros-promos-backend

[nicedexter]

Migros-promos-backend uses a property 'isNew' on a model, which collides with the gm-data one:

@MikeAski

• This property on gm-data has a public visibility, but I'm not sure it should be as is. Could it be renamed to _isNew if it's not meant to be public?
• Could we use a meta namespace to distinct object properties from 'meta state' properties, like object.meta.isNew ?

[MikeAski]

isNew is a property based on an ember-data one...
I agree it is quite cavalier from a persistence layer to use such symbols, and also think we should isolate them inside a namespace, like you suggest.