FR: allow system user to be specified

[jamincollins]

Is your feature request related to a problem? Please describe

Much of the installed software assumes that the system user is pi and and the user's home directory is /home/pi.

Describe the solution you'd like

I would like to be able to specify the username.

Describe alternatives you've considered

Scripting a solutions to rename the user and update all the references.

Additional information

No response

[miklschmidt]

There's a very hard dependency on the environment including the pi user throughout all RatOS repositories right now. It's definitely something that needs to be abstracted, but it doesn't have a particularly high priority at the moment.