Follow up for api completeness

[A5308Y]

See #43.

• Validate unvalidated models by example by ensuring these endpoints return a fitting model in a vcr spec. -> There are some complications with disabled features and missing data on our demo product. This includes fixing all pending specs.
• Ensure attribute call parameters are all in the same order.
• Find a consistent way of aligning attribute parameters
• Rename unvalidated to without_open_api_schema.
• Discuss if specification-logic should be in model or separate.