Add documentation (#96)

README.md

docs/Makefile

docs/_static/composability/diagram.png

docs/_static/composability/diagram_b0.png

docs/_static/composability/diagram_b1.png

docs/_static/composability/diagram_q1.png

docs/_static/composability/diagram_q2.png

docs/conf.py

docs/getting_started/installation.md

docs/getting_started/overview.rst

docs/getting_started/starter_example.md

docs/how_to/composability.md

docs/how_to/cost_analysis.md

docs/how_to/custom_llms.md

docs/how_to/custom_prompts.md

docs/how_to/data_connectors.md

docs/how_to/embeddings.md

docs/how_to/insert.md

docs/how_to/overview.rst

docs/index.rst