3-tier PSP replacement proposal

[Tim Allclair]

I've written up a new proposal based on the ideas we discussed in the last PSP replacement breakout meeting:

https://docs.google.com/document/d/1dpfDF3Dk4HhbQe74AyCpzUYMjp4ZhiEgGXSMpVWLlqQ/edit?usp=sharing

Jordan Liggitt has also implemented a proof of concept, and will give a demo at the next breakout session (tomorrow).

If possible, please try to review the proposal prior to the PSP breakout meeting so that we can discuss it effectively.

Thank you! Looking forward to our discussion tomorrow.

-- Tim Allclair