chore: add best practices section in docs

docs/operations/best-practices/udf.md

@@ -0,0 +1,25 @@
+# User Defined Functions
+
+Few guidelines and tips to help with common use cases and FAQs for UDFs
+
+## High latency operations in UDF
+
+If running a user code which has very high latency or high processing time
+
+1. Increase the `lookbackSeconds` for the autoscaling - This dictates how many seconds to look back for vertex average 
+processing rate (tps) and pending messages calculation, defaults to `120`. In case of tasks taking longer than 
+this duration, you need to increase`lookbackSeconds` so that the calculated average rate and pending messages won't 
+be 0 during the silent period. Refer [Autoscaling](../../user-guide/reference/autoscaling.md) for more information  
+```yaml
+apiVersion: numaflow.numaproj.io/v1alpha1
+kind: Pipeline
+metadata:
+  name: my-pipeline
+spec:
+  vertices:
+    - name: my-vertex
+      scale:
+        lookbackSeconds: 120 # Optional, defaults to 120.
+        ....
+```
+

mkdocs.yml

@@ -128,6 +128,8 @@ nav:
           - operations/metrics/metrics.md
           - operations/grafana.md
       - Security: operations/security.md
+      - Best Practices:
+        - UDF: "operations/best-practices/udf.md"
   - Contributor Guide:
       - development/development.md
       - Specifications: