Proposal: Describe possible project structure and implications

Initial thoughts around scoping Kubernetes resources to projects and the associated implications.

Intended as a complement to #891, but with more detail on the implementation consequences of project scoping throughout the stack.

Would like to get general agreement on an outline to proceed against to support an initial prototype in next couple weeks.
However, let me reframe that.  What I want to understand in the proposal is whether at the very high end of projects we have a clear understanding of what the limits will be at current and whether the next higher level of scale requires significant redesign.