refactor: switch to nammed docker volumes

docker-compose.yml

@@ -4,7 +4,7 @@ services:
     container_name: wireguard
     restart: always
     volumes:
-      - ./wireguard-server/config:/config
+      - wireguard_config:/config
       - /lib/modules:/lib/modules
     cap_add:
       - NET_ADMIN
@@ -24,3 +24,6 @@ services:
     ports:
       - 51820:51820/udp
 
+volumes:
+  wireguard_config:
+    external: true