Add support for stella_en_400M_v5 and add to model zoo

## Description
Add https://huggingface.co/dunzhang/stella_en_400M_v5 to public model zoo.

Will this change the current api? How?
no

Who will benefit from this enhancement?
users of djl

## References
In the English sub 1b parameters category, this model is number one with a large margin.

Start by locating how DJL's public model zoo registers English sub-1B models, then compare the Hugging Face stella_en_400M_v5 entry with neighboring models. Done means the referenced model is available in the public model zoo without changing the current API.

Written by the indexing model from the issue text.