Ability to manage Desktop Environments

[x-0D]

Is your feature request related to a problem? Please describe.

I'm always frustrated when I want to set up a fresh graphical environment on a non-NixOS distribution. System-manager looks like a glimpse in darkness, but currently there is no straightforward way to install and manage display managers or desktop environments, which limits the usability of the tool for users who want a complete desktop experience.

Describe the solution you'd like

I would like to see an enhancement in System Manager that allows users to easily install and configure a display manager (such as GDM) and the GNOME session. This feature should enable users to define these components in their system configuration and have System Manager handle the installation and setup seamlessly.

Describe alternatives you've considered

As an alternative, users can manually install and configure a display manager and GNOME session using traditional package management methods, but this approach is cumbersome and defeats the purpose of using System Manager for a unified configuration management experience. Another option would be to use NixOS directly, but that requires switching distributions, which is not feasible for everyone.

Additional context

Adding this feature would significantly enhance the appeal of System Manager for users who prefer managing their systems with Nix while still wanting to maintain a graphical desktop environment.