feat: Add Support for Ollama

[twosom]

Description

This PR contains these changes

• add support for Ollama with text generation
• add support for Ollama with embedding

fixes #12

Usage Example

text-generation

OllamaModelOptions modelOptions = OllamaModelOptions.builder()
        .modelName("phi4:14b")
        .build();

LangchainModelHandler handler = new LangchainModelHandler(modelOptions, prompt);

embedding

final OllamaEmbeddingModelOptions embeddingOptions = OllamaEmbeddingModelOptions.builder()
                .modelName("nomic-embed-text:latest")
                .build();

EmbeddingModelHandler handler = new EmbeddingModelHandler(embeddingOptions);

[Ganeshsivakumar]

Thanks for your work, @twosom ! The changes look great, we're are good to merge