making types more explicit across codebase

[emrgnt-cmplxty]

[!IMPORTANT] This pull request makes types more explicit across the codebase by removing the ollama provider, renaming LiteCompletionProvider to LiteLLMCompletionProvider, and updating type hints to use Union for multiple provider types.

• Behavior:
  • Removed ollama provider from check_llm_reqs() in docker_utils.py and supported_providers in embedding.py.
  • Updated check_llm_reqs() to remove include_ollama parameter.
• Renames:
  • Renamed LiteCompletionProvider to LiteLLMCompletionProvider.
• Type Annotations:
  • Updated type hints to use Union for multiple provider types in rag.py, abstractions.py, auth_router.py, base_router.py, ingestion_router.py, kg_router.py, management_router.py, retrieval_router.py, app.py, factory.py, deduplication.py, deduplication_summary.py.
• Providers:
  • Removed OllamaEmbeddingProvider from embeddings/__init__.py and ollama.py.
  • Updated SupabaseAuthProvider to raise exceptions for unimplemented methods in supabase.py.
• Tests:
  • Updated tests to reflect provider renames in conftest.py and test_litellm_llm_provider.py.

^{This description was created by for cd843b51f11f954a51553057f666da757d22d588. It will automatically update as commits are pushed.}