As an API designer, I want to have all endpoints and options clearly defined, so I can ensure consistency and challenge the design with the community and with customers.

Acceptance Criteria

• The whole API is defined as proto according to Resources API Design #7592 and Cluster the new API #7649
• The docs from Cluster the new API #7649 are updated according to new learnings
• The API Guidelines from Resources API Design #7592 are updated according to new learnings
• Subissues defined with Cluster the new API #7649 are updated according to new learnings