Update bandwidth limit config syntax

extra/ffmuc_welcome.conf

@@ -96,6 +96,11 @@
         },
       },
     },
+    bandwidth_limit = {
+      enabled = false,
+      egress = 1500,
+      ingress = 12000,
+    },
   },
 
   autoupdater = {
@@ -135,13 +140,5 @@
     },
   },
 
-  simple_tc = {
-    mesh_vpn = {
-      ifname = 'mesh-vpn',
-      enabled = false,
-      limit_egress = 1200,
-      limit_ingress = 12000,
-    },
-  },
 }
 -- vim: set ft=lua:ts=2:sw=2:et