[Feature Request] Allow docker process to run as different user

It has become somehow a standard to read the env vars PUID and GUID to start the process as a different user/group.

This feature request is to modify the docker entrypoint to allow for dynamic users.

The reason behind is that if we want to mount a directory into the container instead of using volumes we can have data being created as a specific user, explicitly i'm looking for the data in /app/data/storage

If this is a feature that would be accepted I'm willing to contribute the change.