Feature add n8 n (#1468)

* feat(n8n): 添加n8n工作流API支持

添加n8n工作流API作为新的运行器类型，支持通过webhook调用n8n工作流，并提供多种认证方式（Basic、JWT、Header）。新增N8nAuthFormComponent用于处理n8n认证表单联动，并更新相关配置文件和测试用例。

* chore: remove pip mirror url

* perf: simplify ret def of pipeline metadata

* feat(n8n): raise exc instead of ret as normal msg

* perf: add var `user_message_text`

* chore(n8n): migration and default config

* chore: required database version

---------

Co-authored-by: hengwei.wang <@>
Co-authored-by: Junyan Qin <rockchinq@gmail.com>

templates/default-pipeline-config.json

@@ -58,6 +58,18 @@
             "api-key": "your-api-key",
             "app-id": "your-app-id",
             "references-quote": "参考资料来自:"
+        },
+        "n8n-service-api": {
+            "webhook-url": "http://your-n8n-webhook-url",
+            "auth-type": "none",
+            "basic-username": "",
+            "basic-password": "",
+            "jwt-secret": "",
+            "jwt-algorithm": "HS256",
+            "header-name": "",
+            "header-value": "",
+            "timeout": 120,
+            "output-key": "response"
         }
     },
     "output": {