feat: Add Debian packaging script, enhance configuration loading with multi-path support, and enable config saving.

config.json

@@ -8,12 +8,20 @@
     {
       "name": "Bar Printer",
       "ip": "192.168.1.201"
+    },
+    {
+      "name": "test printe",
+      "ip": "192.168.1.202"
     }
   ],
   "receipt_printers": [
     {
       "name": "Main Cashier",
       "usb_id": "1fc9:2016"
+    },
+    {
+      "name": "",
+      "usb_id": ""
     }
   ]
 }