feat: Add OpenAI Conversations API (#3429)

# What does this PR do?

Initial implementation for `Conversations` and `ConversationItems` using
`AuthorizedSqlStore` with endpoints to:
- CREATE
- UPDATE
- GET/RETRIEVE/LIST
- DELETE

Set `level=LLAMA_STACK_API_V1`.

NOTE: This does not currently incorporate changes for Responses, that'll
be done in a subsequent PR.

Closes https://github.com/llamastack/llama-stack/issues/3235

## Test Plan
- Unit tests
- Integration tests

Also comparison of [OpenAPI spec for OpenAI
API](https://github.com/openai/openai-openapi/tree/manual_spec)
```bash
oasdiff breaking --fail-on ERR docs/static/llama-stack-spec.yaml https://raw.githubusercontent.com/openai/openai-openapi/refs/heads/manual_spec/openapi.yaml --strip-prefix-base "/v1/openai/v1" \
--match-path '(^/v1/openai/v1/conversations.*|^/conversations.*)'
```

Note I still have some uncertainty about this, I borrowed this info from
@cdoern on https://github.com/llamastack/llama-stack/pull/3514 but need
to spend more time to confirm it's working, at the moment it suggests it
does.

UPDATE on `oasdiff`, I investigated the OpenAI spec further and it looks
like currently the spec does not list Conversations, so that analysis is
useless. Noting for future reference.

---------

Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

tests/unit/utils/sqlstore/test_sqlstore.py

@@ -368,6 +368,32 @@ async def test_where_operator_gt_and_update_delete():
         assert {r["id"] for r in rows_after} == {1, 3}
 
 
+async def test_batch_insert():
+    with TemporaryDirectory() as tmp_dir:
+        db_path = tmp_dir + "/test.db"
+        store = SqlAlchemySqlStoreImpl(SqliteSqlStoreConfig(db_path=db_path))
+
+        await store.create_table(
+            "batch_test",
+            {
+                "id": ColumnType.INTEGER,
+                "name": ColumnType.STRING,
+                "value": ColumnType.INTEGER,
+            },
+        )
+
+        batch_data = [
+            {"id": 1, "name": "first", "value": 10},
+            {"id": 2, "name": "second", "value": 20},
+            {"id": 3, "name": "third", "value": 30},
+        ]
+
+        await store.insert("batch_test", batch_data)
+
+        result = await store.fetch_all("batch_test", order_by=[("id", "asc")])
+        assert result.data == batch_data
+
+
 async def test_where_operator_edge_cases():
     with TemporaryDirectory() as tmp_dir:
         db_path = tmp_dir + "/test.db"