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>

docs/sidebars.ts

@@ -41,6 +41,15 @@ const sidebars: SidebarsConfig = {
             'concepts/apis/api_leveling',
           ],
         },
+        {
+          type: 'category',
+          label: 'Vector Stores',
+          collapsed: true,
+          items: [
+            'concepts/file_operations_vector_stores',
+            'concepts/vector_stores_configuration',
+          ],
+        },
         'concepts/distributions',
         'concepts/resources',
       ],