Bitcoin Design Guide Jam Session #45

In this work session we went over the outstanding tasks in milestone 18, with the big one being the Payjoin case study. We also talked about a handful of other tasks, as well as structuring future milestones based on mini-projects that we all collaborate on together.

Roadmap:
https://github.com/orgs/BitcoinDesign/projects/2

Issue:
https://github.com/BitcoinDesign/Meta/issues/465