Make an own company document public

Makes the caller's document readable by every company, drops its pending access requests, and returns it as it now stands — the document itself, not wrapped in { data, metadata }. confirmation must be the literal public. A document the caller cannot see answers 404. A document filed on a different company than its owner (strictly shared between two parties) answers 409 strictly_shared_document_cannot_be_made_public, and one that already has an approved share answers 409 company_document_status_cannot_reverse. Only the owner may do it (403). A document that is already public is returned unchanged. When the document is of a type that maps a cascade-tracing node, a publicly-shared event is published either way.