Remove models that are just wrappers for lists

[DiamondJoseph]

DeviceResponse, PlanResponse and TaskListResponse base models all just wrap a list. We could just return the list.

[callumforrester]

See the top answer here: https://softwareengineering.stackexchange.com/questions/286293/whats-the-best-way-to-return-an-array-as-a-response-in-a-restful-api

[stan-dot]

petition to close as not planned @DiamondJoseph

[callumforrester]

I wanted to make sure this is documented in @keithralphs' service design guidelines, once I've checked I'll close this.

[stan-dot]

link for reference https://gitlab.diamond.ac.uk/sscc-docs/developer-guide/-/merge_requests/115