Upgrading to `guidance>=0.1.0`, restructuring `llms` folder, adding documentation

[parkervg]

The previous version was built on guidance 0.0.64, the older version built with handlebars-style syntax. However, this meant that we had to use an old version of OpenAI. This PR refactors BlendSQL to use the newer 0.1.0 version of guidance.

• Reformatted _programs.py to use guidance>=0.1.0 syntax
  • Found in blendsql/_programs.py, each LLM ingredient now has a program represented as a Python script. This is cleaner imo, since we can use context handlers instead of rewriting completion/chat style prompts with the handlebar syntax
• Restructured llms folder
  • I moved them to blendsql/llms, and created a remote/local subdirectories
  • num_prompt_tokens is now updated with each predict call
  • A separate AzureOpenaiLLM class was added
• Stored test dbs on huggingface at https://huggingface.co/datasets/parkervg/blendsql-test-dbs
  • The dbs will be fetched from the hub before running tests
• Added documentation with mkdocs
  • To be deployed via github pages (screenshot below)

[parkervg]

https://parkervg.github.io/blendsql/