feat: support postgresql inference store (#2310)

# What does this PR do?
* Added support postgresql inference store
* Added 'oracle' template that demos how to config postgresql stores
(except for telemetry, which is not supported currently)


## Test Plan

llama stack build --template oracle --image-type conda --run
LLAMA_STACK_CONFIG=http://localhost:8321 pytest -s -v tests/integration/
--text-model accounts/fireworks/models/llama-v3p3-70b-instruct -k
'inference_store'

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]