feat & fix

- support openwrt
- save server info failed if connect error
- support ssh 'none' auth

lib/data/model/server/memory.dart

@@ -2,14 +2,12 @@ class Memory {
   int total;
   int used;
   int free;
-  int shared;
   int cache;
   int avail;
   Memory(
       {required this.total,
       required this.used,
       required this.free,
-      required this.shared,
       required this.cache,
       required this.avail});
 }