Make embedding generation go through inference (#606)

This PR does the following:
1) adds the ability to generate embeddings in all supported inference
providers.
2) Moves all the memory providers to use the inference API and improved
the memory tests to setup the inference stack correctly and use the
embedding models

This is a merge from #589 and #598

llama_stack/providers/remote/memory/chroma/chroma.py

@@ -13,8 +13,7 @@ import chromadb
 from numpy.typing import NDArray
 
 from llama_stack.apis.memory import *  # noqa: F403
-
-from llama_stack.providers.datatypes import MemoryBanksProtocolPrivate
+from llama_stack.providers.datatypes import Api, MemoryBanksProtocolPrivate
 from llama_stack.providers.inline.memory.chroma import ChromaInlineImplConfig
 from llama_stack.providers.utils.memory.vector_store import (
     BankWithIndex,
@@ -87,10 +86,14 @@ class ChromaIndex(EmbeddingIndex):
 
 class ChromaMemoryAdapter(Memory, MemoryBanksProtocolPrivate):
     def __init__(
-        self, config: Union[ChromaRemoteImplConfig, ChromaInlineImplConfig]
+        self,
+        config: Union[ChromaRemoteImplConfig, ChromaInlineImplConfig],
+        inference_api: Api.inference,
     ) -> None:
         log.info(f"Initializing ChromaMemoryAdapter with url: {config}")
         self.config = config
+        self.inference_api = inference_api
+
         self.client = None
         self.cache = {}
 
@@ -127,10 +130,9 @@ class ChromaMemoryAdapter(Memory, MemoryBanksProtocolPrivate):
                 metadata={"bank": memory_bank.model_dump_json()},
             )
         )
-        bank_index = BankWithIndex(
-            bank=memory_bank, index=ChromaIndex(self.client, collection)
+        self.cache[memory_bank.identifier] = BankWithIndex(
+            memory_bank, ChromaIndex(self.client, collection), self.inference_api
         )
-        self.cache[memory_bank.identifier] = bank_index
 
     async def unregister_memory_bank(self, memory_bank_id: str) -> None:
         await self.cache[memory_bank_id].index.delete()
@@ -166,6 +168,8 @@ class ChromaMemoryAdapter(Memory, MemoryBanksProtocolPrivate):
         collection = await maybe_await(self.client.get_collection(bank_id))
         if not collection:
             raise ValueError(f"Bank {bank_id} not found in Chroma")
-        index = BankWithIndex(bank=bank, index=ChromaIndex(self.client, collection))
+        index = BankWithIndex(
+            bank, ChromaIndex(self.client, collection), self.inference_api
+        )
         self.cache[bank_id] = index
         return index