bundles/nginx: determine worker processes by cpu count by default

bundles/nginx/metadata.py

@@ -17,12 +17,20 @@ defaults = {
         },
     },
     'nginx': {
-        'worker_processes': 4,
+        'worker_connections': 768,
-        'worker_connections': 1000,
     },
 }
 
 
+@metadata_reactor
+def worker_processes(metadata):
+    return {
+        'nginx': {
+            'worker_processes': metadata.get('vm/cpu', 2),
+        },
+    }
+
+
 @metadata_reactor
 def letsencrypt(metadata):
     if not node.has_bundle('letsencrypt'):