SMART on FHIR Access Control: Patient Review and Revocation

A few things about SMART on FHIR access revocation

1. The key from an EHR perspective is to ensure that patients are informed about what they're sharing and have easy ways to stop if/when they want to.

**Management page in the portal**. The patient portal needs a page (advertised in the `.well-known/smart-configuration` document as the "management endpoint") where patients can review and revoke outstanding access grants.

**Notifications and reminders**. EHRs should think about how to surface information to patients about sharing decisions. For example, via e-mail or mobile app notifications to let patients know things like "A new app has connected to your record" or "Three apps currently have access to your record" or whatever. These reminders can provide links back to the management page in the portal, so patients can easily adjust sharing

Access revocation can happen in response to patient choices outside of an app, and we standardize this at the level of revocking a complete grant. This helps avoid surprises for the app. For example, would be confusing for an app to receive 3 scopes of access (say, allergies, immunizations, and medications) but then have one of these scopes disappear while the access token continued working.

See discussion at https://chat.fhir.org/#narrow/stream/...