restic: raise a failed backup, a failed thinning and a refused retention as the module's health (novox/hq issue 454)

A failed night was a journal line only, so a typo in a retention setting
let the repository grow until a disk filled. The night and the measuring
now run as processes the node-engine judges: the night by backup_health,
which is unhealthy for a module not backed up, a night that did not run,
a failed thinning or a missing retention file, and waits naming the
setting when one is refused; the measuring by its unit. A file lock
keeps a night and the tool runtime's now and restore apart.

The retention file is root's alone, so the account reads it through sudo:
until now every night would have refused it as unreadable. Every machine
has the file, so a missing one is refused instead of thinned by 14/8/6.
backed-up says the retention in force and the last thinning per module.

modules/restic/module.json

@@ -12,6 +12,11 @@
       ]
     }
   ],
+  "tools": [
+    "backup_health",
+    "backup_delete_retired",
+    "backup_deleted"
+  ],
   "own-secrets": {
     "repository": "${dir:state}/repository.secret"
   },
@@ -92,6 +97,53 @@
       "id": "sqlite",
       "type": "package",
       "package": "sqlite"
+    },
+    {
+      "id": "night",
+      "type": "process",
+      "name": "restic-night",
+      "artifact": "tools",
+      "run": [
+        "./restic-backups",
+        "night"
+      ],
+      "user": "${machine:account}",
+      "env": {
+        "MESH_BACKUP_DECLARED": "${dir:state}/backups.conf",
+        "MESH_BACKUP_REPOSITORY": "${dir:repository}",
+        "MESH_BACKUP_PASSWORD_FILE": "${dir:state}/repository.secret",
+        "MESH_BACKUP_STATE": "${dir:state}",
+        "MESH_BACKUP_DATA": "${dir:state}/data.conf"
+      },
+      "health": {
+        "kind": "tool",
+        "tool": "backup_health",
+        "interval": "60s",
+        "timeout": "20s",
+        "looks": 2,
+        "grace": "60s"
+      }
+    },
+    {
+      "id": "measure",
+      "type": "process",
+      "name": "restic-measure",
+      "artifact": "tools",
+      "run": [
+        "./restic-backups",
+        "measure"
+      ],
+      "user": "${machine:account}",
+      "env": {
+        "MESH_BACKUP_DECLARED": "${dir:state}/backups.conf",
+        "MESH_BACKUP_REPOSITORY": "${dir:repository}",
+        "MESH_BACKUP_PASSWORD_FILE": "${dir:state}/repository.secret",
+        "MESH_BACKUP_STATE": "${dir:state}",
+        "MESH_BACKUP_DATA": "${dir:state}/data.conf"
+      },
+      "health": {
+        "kind": "unit"
+      }
     }
   ],
   "build": {