Allow configure server_ip and port

https://github.com/alexbelgium/hassio-addons/issues/647

seafile/config.json

@@ -58,6 +58,8 @@
     "PUID": 1000,
     "SEAFILE_ADMIN_EMAIL": "me@example.com",
     "SEAFILE_ADMIN_PASSWORD": "a_very_secret_password",
+    "SERVER_IP": "homeassistant.local",
+    "PORT": "8082",
     "TZ": "Europe/Paris",
     "URL": "seafile.example.com",
     "data_location": "/share/seafile",
@@ -82,6 +84,8 @@
     "PUID": "int",
     "SEAFILE_ADMIN_EMAIL": "email",
     "SEAFILE_ADMIN_PASSWORD": "password",
+    "SERVER_IP": "str?",
+    "PORT": "str?",
     "TZ": "str?",
     "URL": "str",
     "cifspassword": "str?",