fix: added missing code from various LN PRs

lib/routes/probeLnRoutes.js

@@ -0,0 +1,20 @@
+const express = require('express')
+const router = express.Router()
+
+const plugins = require('../plugins')
+const settingsLoader = require('../new-settings-loader')
+
+function probe (req, res, next) {
+  // TODO: why req.settings is undefined?
+  settingsLoader.loadLatest()
+    .then(settings => {
+      const pi = plugins(settings, req.deviceId)
+      return pi.probeLN('LN', req.body.address)
+        .then(r => res.status(200).send({ hardLimits: r }))
+        .catch(next)
+    })
+}
+
+router.get('/', probe)
+
+module.exports = router