[FEAT] Environment variable to change default user account name from abc to something else

[cmdpedro]

Is this a new feature request?

• [x] I have searched the existing issues

Wanted change

It would be great if we could change the default user account name from abc to something else via an environment variable.

Reason for change

While abc works just fine, having a way to change it would allow existing user scripts and tools to work in expected ways.

Proposed code change

To achieve this, one could possibly adjust the base image and init script.