Write documentation on where to store notes on visits

[saewitz]

https://github.com/masslight/ottehr/blob/2fdda8defedd7d5a95dc44ece02d1ce0a9c0c80c/packages/telemed-ehr/zambdas/src/save-chart-data/index.ts

[rzinger]

may need a bit of help how to document; also I believe a FHIR model would be useful, so i'll draw one with ExcaliDraw, but... i m not sure how it translates into our standard graphics, etc.