Chore: specify default language parameter to paddle with `DEFAULT_PADDLE_LANG` (#2065)
Close: https://github.com/Unstructured-IO/unstructured-api/issues/247
### Summary
User now can specify default [paddle lang
code](https://github.com/Mushroomcat9998/PaddleOCR/blob/main/doc/doc_en/multi_languages_en.md#5-support-languages-and-abbreviations)
with env `DEFAULT_PADDLE_LANG` before we have the language mapping for
paddle
### Test
* in your unstructured API env, cd to unstructured repo and install it
locally with `pip install -e .`
* check out to this branch
* run paddle on intel chip:
```
pip install paddlepaddle
pip install "unstructured.PaddleOCR"
export OCR_AGENT=paddle
export DEFAULT_PADDLE_LANG=ch
make run-web-app
```
* curl:
```
curl -X 'POST' 'http://localhost:8000/general/v0/general' -H 'accept: application/json' -F 'files=@sample-docs/english-and-korean.png' | jq -C . | less -R
```
* expected to see `INFO Loading paddle with CPU on language=ch...` in
log info
unstructured
6c9990b0 - Chore: specify default language parameter to paddle with `DEFAULT_PADDLE_LANG` (#2065)
