postgres

# What does this PR do?


## Test Plan

llama_stack/templates/postgres-demo/build.yaml

@@ -0,0 +1,24 @@
+version: '2'
+distribution_spec:
+  description: Quick start template for running Llama Stack with several popular providers
+  providers:
+    inference:
+    - remote::fireworks
+    - remote::vllm
+    vector_io:
+    - remote::chromadb
+    safety:
+    - inline::llama-guard
+    agents:
+    - inline::meta-reference
+    telemetry:
+    - inline::meta-reference
+    tool_runtime:
+    - remote::brave-search
+    - remote::tavily-search
+    - inline::rag-runtime
+    - remote::model-context-protocol
+image_type: conda
+additional_pip_packages:
+- asyncpg
+- sqlalchemy[asyncio]