Declare every module's data; the backup holder measures it (hq ADR 0233)

Backup lines are derived from each module's data section instead of written by hand; the holder
measures declared items, reads the array under them, and deletes a retired item only after a last
restore point; the Go providers say each held consumer's size so an empty replacement is seen.

modules/mailu/module.json

@@ -144,6 +144,89 @@
       "why": "the admin API, which this module's own code reaches on loopback from the node's runtime now that it runs outside the mailu network"
     }
   ],
+  "data": {
+    "own": [
+      {
+        "id": "mail",
+        "path": "${dir:data-mail}",
+        "class": "valuable",
+        "why": "every mailbox"
+      },
+      {
+        "id": "dkim",
+        "path": "${dir:data-dkim}",
+        "class": "valuable",
+        "why": "the domain's signing keys; a new one means a new DNS record"
+      },
+      {
+        "id": "data",
+        "path": "${dir:data-data}",
+        "class": "valuable",
+        "why": "the server's own data"
+      },
+      {
+        "id": "dav",
+        "path": "${dir:data-dav}",
+        "class": "valuable",
+        "why": "calendars and contacts"
+      },
+      {
+        "id": "webmail",
+        "path": "${dir:data-webmail}",
+        "class": "valuable",
+        "why": "the webmail's own data: its users' settings and address books"
+      },
+      {
+        "id": "queue",
+        "path": "${dir:data-mailqueue}",
+        "class": "valuable",
+        "why": "mail accepted and not yet delivered, kept nowhere else"
+      },
+      {
+        "id": "filter",
+        "path": "${dir:data-filter}",
+        "class": "rebuildable",
+        "why": "the spam filter's learned statistics; it learns again"
+      },
+      {
+        "id": "certs",
+        "path": "${dir:data-certs}",
+        "class": "rebuildable",
+        "why": "certificates, issued again"
+      },
+      {
+        "id": "automx",
+        "path": "${dir:data-automx}",
+        "class": "rebuildable",
+        "why": "client autoconfiguration, written again"
+      },
+      {
+        "id": "fetchmail",
+        "path": "${dir:data-fetchmail}",
+        "class": "rebuildable",
+        "why": "which remote messages were fetched; lost, some are fetched twice"
+      },
+      {
+        "id": "clamav",
+        "path": "${dir:data-clamav}",
+        "class": "cache",
+        "why": "virus signatures, downloaded again"
+      },
+      {
+        "id": "redis",
+        "path": "${dir:data-redis}",
+        "class": "cache",
+        "why": "the filter's working set"
+      }
+    ],
+    "consumers": {
+      "smtp": {
+        "class": "valuable",
+        "in": "mail",
+        "why": "a consumer's mailbox holds the only copy of its mail"
+      }
+    }
+  },
   "resources": [
     {
       "id": "mesh-state",
@@ -562,12 +645,5 @@
       "failregex": "^.*(?:imap|pop3|submission|managesieve)-login: .*\\(auth failed, \\d+ attempts(?: in \\d+ secs)?\\):.*rip=<HOST>(?:,|$)",
       "jail": "backend = systemd\njournalmatch = CONTAINER_NAME=mailu-front\nport = smtp,submission,submissions,imap,imaps,pop3,pop3s\nmaxretry = 3\nfindtime = 1d\nbantime = 1d"
     }
-  ],
-  "contributions": [
-    {
-      "seat": "node-backup",
-      "kind": "backup",
-      "content": "path ${dir:data-mail}\npath ${dir:data-dkim}\npath ${dir:data-data}\npath ${dir:data-dav}\npath ${dir:data-webmail}\n"
-    }
   ]
 }