custom selection of integrations to work with core

custom selection of integrations to work with core
pip install llama-index-core
pip install llama-index-llms-openai
pip install llama-index-llms-ollama
pip install llama-index-embeddings-huggingface
```

Examples are in the `docs/examples` folder. Indices are in the `indices` folder (see list of indices below).