Simplify integrating Ollama, OpenAI proxies with Khoj on first run

- Integrate with Ollama or other openai compatible APIs by simply
  setting `OPENAI_API_BASE' environment variable in docker-compose etc.
- Update docs on integrating with Ollama, openai proxies on first run
- Auto populate all chat models supported by openai compatible APIs
- Auto set vision enabled for all commercial models

- Minor
  - Add huggingface cache to khoj_models volume. This is where chat
  models and (now) sentence transformer models are stored by default
  - Reduce verbosity of yarn install of web app. Otherwise hit docker
  log size limit & stops showing remaining logs after web app install
  - Suggest `ollama pull <model_name>` to start it in background

docker-compose.yml

@@ -37,6 +37,7 @@ services:
     volumes:
       - khoj_config:/root/.khoj/
       - khoj_models:/root/.cache/torch/sentence_transformers
+      - khoj_models:/root/.cache/huggingface
     # Use 0.0.0.0 to explicitly set the host ip for the service on the container. https://pythonspeed.com/articles/docker-connection-refused/
     environment:
       - POSTGRES_DB=postgres
@@ -48,12 +49,17 @@ services:
       - KHOJ_DEBUG=False
       - KHOJ_ADMIN_EMAIL=username@example.com
       - KHOJ_ADMIN_PASSWORD=password
-      # Uncomment lines below to use chat models by each provider.
+      # Uncomment line below to use with Ollama running on your local machine at localhost:11434.
+      # Change URL to use with other OpenAI API compatible providers like VLLM, LMStudio etc.
+      # - OPENAI_API_BASE=http://host.docker.internal:11434/v1/
+      #
+      # Uncomment appropriate lines below to use chat models by OpenAI, Anthropic, Google.
       # Ensure you set your provider specific API keys.
       # ---
       # - OPENAI_API_KEY=your_openai_api_key
       # - GEMINI_API_KEY=your_gemini_api_key
       # - ANTHROPIC_API_KEY=your_anthropic_api_key
+      #
       # Uncomment the necessary lines below to make your instance publicly accessible.
       # Replace the KHOJ_DOMAIN with either your domain or IP address (no http/https prefix).
       # Proceed with caution, especially if you are using anonymous mode.