Adding readme with link to a repo containing a comprehensive multiagent postgreSQL data management example (#6443)

## Why are these changes needed?

Requesting to add a new example folder under Python samples so that
AutoGen(0.4+) users can easily find this comprehensive example of using
agents and Groupchats to build a multi-agent data management system for
Azure postgreSQL. Readme contains link to a repo with comprehensive
multiagent postgreSQL data management example

## Related issue number

N/A

## Checks
N/A (only a readme file)
- [ ] I've included any doc changes needed for
<https://microsoft.github.io/autogen/>. See
<https://github.com/microsoft/autogen/blob/main/CONTRIBUTING.md> to
build and test documentation locally.
- [ ] I've added tests (if relevant) corresponding to the changes
introduced in this PR.
- [ ] I've made sure all auto checks have passed.

Co-authored-by: Mehrsa Golestaneh <mgolestaneh@microsoft.com>
Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>

Author: 3 people

python/samples/agentchat_azure_postgresql/README.md

@@ -0,0 +1,12 @@
+# **Multi-Agent PostgreSQL Data Management System with AutoGen and Azure PostgreSQL**
+
+
+<div align="center">
+  <img src="https://github.com/mehrsa/MultiAgent_Azure_PostgreSQL_AutoGen0.4/blob/main/misc/Drawing%203.png" alt="Architecture">
+</div>
+
+Go to below repository to try out a demo demonstrating how to build a **multi-agent AI system** for managing shipment data stored on an Azure PostgreSQL database:
+
+[MultiAgent_Azure_PostgreSQL_AutoGen](https://github.com/Azure-Samples/MultiAgent_Azure_PostgreSQL_AutoGen0.4/tree/main)
+
+