Add notes on shared configuration

I'd appreciative comments on:

• If it seems like a reasonable next step to try and resolve formats + how to do a best-practise "configure me" request over email, then reevaluate where we're at. Learning this by doing -> will inform on the "selection criteria" and formats involved for automation ("Appendix A"). And, this is by far the most important challenge to make progress on quickly as more community members are onboarded to this space.
• Things you agree/disagree with, or if obvious things are missing

I intent to merge these notes ~next week, and before I do so I will do a best-effort stab at incorporating comments and/or copy-pasting them into the document to not lose track of them. I'm also happy to take your input verbally in the other section of 2024-11-19's sigsum weekly.