feat: add incoming webhook API support with configurable endpoints

- Implemented the incoming webhook API to handle alerts from external applications.
- Added configuration options for webhook listening address, port, and endpoints in config.go.
- Created WebhookReceiverConfig and WebhookEndpointConfig structures to manage webhook settings.
- Developed WebhookHandler to process incoming requests, validate tokens, and deliver alerts to specified channels.
- Enhanced existing controller interfaces to support alert delivery.
- Updated message rendering to respect Markdown settings for different channels.
- Added tests for webhook functionality and ensured proper error handling.

handler/server.go

@@ -63,7 +63,7 @@ func ServerListHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	params := template.BuildParamsFromServerList()
-	result := template.Render("", params)
+	result := template.Render("", params, false)
 
 	utils.SendSuccessResponse(w, "", map[string]interface{}{
 		"list": result,