cli: Document configuration expected by every endpoint
Contains a commit from https://gitlab.softwareheritage.org/swh/devel/swh-scheduler/-/merge_requests/346
Requires https://gitlab.softwareheritage.org/swh/devel/swh-core/-/merge_requests/355 in order to be formatted correctly, and https://gitlab.softwareheritage.org/swh/devel/swh-docs/-/merge_requests/368 for the links to work