improve configurability of watcher parameters

app/filesWatcher.js

@@ -237,9 +237,9 @@ module.exports = function(config, models){
 
   logger.info('starting watcher')
   var watcher = chokidar.watch(config.userInfo.basePathToWatch+ '/**/*.bkr', {
-    usePolling: true, // more expensive, but works also on GPFS with updates from multiple machines
-    interval: 1000,
-    binaryInterval: 3000
+    usePolling: config.watcher.usePolling, // more expensive, but works also on GPFS with updates from multiple machines
+    interval: config.watcher.interval,
+    binaryInterval: config.watcher.binaryInterval
   });
   watcher.on('add', (path,stats) => {
     addNewNotebook(path, stats)

config/default.hjson

@@ -94,3 +94,8 @@ userInfo: {
   sharedDirInContainer: "/data/shared"
   mySharedDirInContainer: "/data/my-shared"
 }
+watcher{
+  usePolling: true
+  interval: 2000
+  binaryInterval: 6000
+}
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