[memory refactor][2/n] Update faiss and make it pass tests (#830)

See https://github.com/meta-llama/llama-stack/issues/827 for the broader
design.

Second part:

- updates routing table / router code 
- updates the faiss implementation


## Test Plan

```
pytest -s -v -k sentence test_vector_io.py --env EMBEDDING_DIMENSION=384
```

llama_stack/providers/registry/tool_runtime.py

@@ -23,7 +23,7 @@ def available_providers() -> List[ProviderSpec]:
             pip_packages=[],
             module="llama_stack.providers.inline.tool_runtime.memory",
             config_class="llama_stack.providers.inline.tool_runtime.memory.config.MemoryToolRuntimeConfig",
-            api_dependencies=[Api.memory, Api.memory_banks, Api.inference],
+            api_dependencies=[Api.vector_io, Api.vector_dbs, Api.inference],
         ),
         InlineProviderSpec(
             api=Api.tool_runtime,