[Community] Add streaming for maritalk (#13207)

docs/docs/examples/llm/maritalk.ipynb

...dex-integrations/llms/llama-index-llms-maritalk/README.md

...ama-index-llms-maritalk/llama_index/llms/maritalk/base.py

...ntegrations/llms/llama-index-llms-maritalk/pyproject.toml