Consumer API redesign

Re-design Consumer REST API to make it more consistent, flexible and generic (less coupled with the Spline Web UI implementation)

**TBD**

The issue only identifies the Consumer REST API and a broad goal of making it more consistent, flexible, generic, and less coupled to the Spline Web UI. Start by locating the current Consumer API entry points and its REST tests; the issue provides no concrete redesign or acceptance criteria, so completion would require an agreed design and implementation.

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