Journaling: outside archives, and Journal it in mail flow rules

Phase 3 of the journaling spec.

- A journal's destination: builtIn (true for journals stored before) and
  archiveAddress, at least one. Reports to an archive are queued from the
  empty sender, one per address, flagged so they're never journaled.
- A pending record per report. When the queue lets go of one without
  delivering it (refused, expired, deleted), it becomes its own entry in
  the built-in journal under the sending journals' retention, the
  journal's archiveFailures (count, last time, reason) goes up, and the
  audit log records it; if that can't be written it stays queued.
- Journal it: a rule action naming a journal, on mail flow rules and
  beside a DLP rule's block, warn or hold. A journal whose scope chooses
  nobody takes only what rules send it.
- The report lists recipients a rule added or redirected to under
  "Added by rule", by rule name.
- A rule's route is cleared between messages in one SMTP session, with the
  new journal marks; a second message used to keep the first one's route.

tests/src/system/journal.rs: destination validation, a rule-only journal
fed by a rule that also adds a recipient, an unreachable archive's report
kept in the built-in journal with the failure counted, a report delivered
to an archive here and not journaled itself.

crates/jmap-proto/src/object/inbuxa_journal.rs

@@ -31,6 +31,12 @@ pub enum JournalProperty {
     Scope,
     /// How long an entry is kept; each keeps what it was written with.
     RetentionDays,
+    /// Whether entries go into the built-in journal.
+    BuiltIn,
+    /// An outside archive's journal address.
+    ArchiveAddress,
+    /// Reports the archive didn't take: how many, when and why last.
+    ArchiveFailures,
     CreatedBy,
     CreatedAt,
     UpdatedAt,
@@ -59,6 +65,9 @@ impl Property for JournalProperty {
             JournalProperty::Direction => "direction",
             JournalProperty::Scope => "scope",
             JournalProperty::RetentionDays => "retentionDays",
+            JournalProperty::BuiltIn => "builtIn",
+            JournalProperty::ArchiveAddress => "archiveAddress",
+            JournalProperty::ArchiveFailures => "archiveFailures",
             JournalProperty::CreatedBy => "createdBy",
             JournalProperty::CreatedAt => "createdAt",
             JournalProperty::UpdatedAt => "updatedAt",
@@ -77,6 +86,9 @@ impl JournalProperty {
             b"direction" => JournalProperty::Direction,
             b"scope" => JournalProperty::Scope,
             b"retentionDays" => JournalProperty::RetentionDays,
+            b"builtIn" => JournalProperty::BuiltIn,
+            b"archiveAddress" => JournalProperty::ArchiveAddress,
+            b"archiveFailures" => JournalProperty::ArchiveFailures,
             b"createdBy" => JournalProperty::CreatedBy,
             b"createdAt" => JournalProperty::CreatedAt,
             b"updatedAt" => JournalProperty::UpdatedAt,