Document Lifecycle Webhooks

If you wanted to know when a document got signed or a new version got published, you had to poll the API and diff the result yourself.

Document lifecycle events are now webhook subscribable: created, updated, archived, unarchived, deleted, plus the version, signature, and approval sub-events underneath each document. Wire up a webhook once and get notified the moment any of those happen.

The CLI's prb webhook create/update commands cover the same event list, so you can wire this up without leaving your terminal.