Token and username property for "Releases"-widget for dockerhub registry

### Description

I would like to monitor all including my private repos from dockerhub. It would be nice to have to have to more properties in the releases widget:
dockerhub-user
dockerhub-token (PAT)

At the moment I can't retrieve my private repos because I can't pass the authentication to the widget.

I hope this is understandable, please let me know if I need to refine my feature request.

Anyways thanks a lot in advance and also thanks for this great application.