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

Dockerfile

@@ -37,7 +37,7 @@ ENV PYTHONPATH=/app/src:$PYTHONPATH
 
 # Go to the directory src/interface/web and export the built Next.js assets
 WORKDIR /app/src/interface/web
-RUN bash -c "yarn install --frozen-lockfile --verbose && yarn ciexport && yarn cache clean"
+RUN bash -c "yarn install --frozen-lockfile && yarn ciexport && yarn cache clean"
 WORKDIR /app
 
 # Run the Application