Configure user avatar

[tye-exe]

I would love for plasma-manager to have an option for setting the user avatar. It's not the highest priority, but it's just a nice addition.

After a small bit of research & testing (credit to this post https://superuser.com/a/1772789), the user avatar is stored at /var/lib/AccountsService/icons/<username> as a 256x256 PNG file (with no file extension).

I'm not sure how this would be implemented in a reproducible fashion, unless a hash for the PNG file could be used to check against (similar to how nixpkgs works). Furthermore, i don't have any experience with the plasma-manager code-base, but i would be happy to give implementation a go if i am pointed in the correct direction.

[sidmoreoss]

Here's an example of how you can add a custom option like user.user.[userName].icon directly to your NixOS configuration:
GitLab Example - User Icon

This demonstrates how to extend the NixOS module system to include custom options. In this case, it shows how to define a icon setting within the user configuration. You can use this approach to add similar features to your repository, making it easier to manage custom options directly in your NixOS setup.

Refer this https://gitlab.com/lazylinux/nixos/-/blob/master/modules/users/default.nix?ref_type=heads for usage example