Make the messenger's per-channel hourly cap the setting messages-per-hour, default 100 (issue 1476)

modules/messenger/module.json

@@ -132,6 +132,14 @@
       "description": "The kinds of channel set to say only what needs the operator: a walk that delivered with nothing held and nothing open is not told there (ADR 0308 §4); empty is none.",
       "trusted": true,
       "default": []
+    },
+    "messages-per-hour": {
+      "type": "number",
+      "description": "The most messages the mesh sends one channel in an hour, in messages per channel per hour; past it the rest are held and said once as one message (not the tell verb, which has its own cap of 10).",
+      "minimum": 1,
+      "maximum": 1000,
+      "trusted": false,
+      "default": 100
     }
   },
   "resources": [
@@ -155,7 +163,7 @@
       "type": "file",
       "path": "${dir:state}/settings.json",
       "mode": "0600",
-      "takes-config": ["time-zone", "desktop-machines", "only-what-needs-me"],
+      "takes-config": ["time-zone", "desktop-machines", "only-what-needs-me", "messages-per-hour"],
       "merge": "json",
       "template": "files/settings.json",
       "owner": "messenger"