feat: include a default inference store during llama stack build (#3373)

# What does this PR do?

enables completions storage when using `llama stack build --providers` -
 - GET /v1/chat/completions
 - GET /v1/chat/completions/{id}

todo: llama stack build and distro codegen should use the same code
paths

## Test Plan

ci

Author: mattf

llama_stack/cli/stack/_build.py

@@ -45,6 +45,7 @@
 from llama_stack.core.utils.exec import formulate_run_args, run_command
 from llama_stack.core.utils.image_types import LlamaStackImageType
 from llama_stack.providers.datatypes import Api
+from llama_stack.providers.utils.sqlstore.sqlstore import SqliteSqlStoreConfig
 
 DISTRIBS_PATH = Path(__file__).parent.parent.parent / "distributions"
 
@@ -294,6 +295,12 @@ def _generate_run_config(
         if build_config.external_providers_dir
         else EXTERNAL_PROVIDERS_DIR,
     )
+    if not run_config.inference_store:
+        run_config.inference_store = SqliteSqlStoreConfig(
+            **SqliteSqlStoreConfig.sample_run_config(
+                __distro_dir__=(DISTRIBS_BASE_DIR / image_name).as_posix(), db_name="inference_store.db"
+            )
+        )
     # build providers dict
     provider_registry = get_provider_registry(build_config)
     for api in apis: