Spring-ai Ollama: upgrade to batch embedding endpoint API

Ollama is superseding the legacy /api/embeddings embedding endpoint by a new batch embedding /api/embed one.

The new endpoint supports batch embedding and introduces keep-alive and truncates request parameters are introduced.

Update the SpringAI OllamaApi and OllamaEmbeddingModel to leverage the new /api/embed and deprecate the legacy /api/embeddings.