feat: Enhance Vector Stores config with full configurations (#4397)

# What does this PR do?

Enhances the Vector Stores config with full set of appropriate
configurations
- Add FileIngestionParams, ChunkRetrievalParams, and FileBatchParams
subconfigs
- Update RAG memory, OpenAI vector store mixin, and vector store utils
to use configuration
  - Fix import organization across vector store components
  - Add comprehensive vector stores configuration documentation
  - Update docs navigation to include vector store configuration guide
- Delete `memory/constants.py` and move constant values directly into
Pydantic models

## Test Plan
Tests updated + CI

---------

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

tests/unit/core/routers/test_vector_io.py

@@ -156,7 +156,6 @@ async def test_query_rewrite_functionality():
     from unittest.mock import MagicMock
 
     from llama_stack.core.datatypes import QualifiedModel, RewriteQueryParams, VectorStoresConfig
-    from llama_stack.providers.utils.memory.constants import DEFAULT_QUERY_REWRITE_PROMPT
     from llama_stack_api import VectorStoreSearchResponsePage
 
     mock_routing_table = Mock()
@@ -197,7 +196,7 @@ async def test_query_rewrite_functionality():
 
     # Verify default prompt is used
     prompt_text = chat_call_args.messages[0].content
-    expected_prompt = DEFAULT_QUERY_REWRITE_PROMPT.format(query="test query")
+    expected_prompt = "Expand this query with relevant synonyms and related terms. Return only the improved query, no explanations:\n\ntest query\n\nImproved query:"
     assert prompt_text == expected_prompt
 
     # Verify routing table was called with rewritten query and rewrite_query=False