Make NetworkManager plugins optional

[piegamesde]

Issue description

At the moment, the NixOS NetworkManager module includes all plugins that are packaged for NixOS. This is problematic on headless systems, because these modules pull in a ton of gnome dependencies (including gtk), which is not acceptable for a small headless device. I tried overriding those packages with withGnome = false, but they pull in too many graphical dependencies nevertheless.

An option to turn these off (in whatever way) would be appreciated.

Steps to reproduce

1. networkmanager.enable = true;
2. nix-tree path-to-derivation
3. / (search) gtk
4. w (why-depends)

Technical details

Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

Ping maintainers

@NixOS/freedesktop

[piegamesde]

I just came up with another issue with the current plugin implementation: there is no module-level way to override the packages of these plugins. Thus, the only way to achieve this is a global system overlay. However, this will cause a rebuild of all reverse-dependencies, which may not be desired.

[jtojnar]

See #84433 (comment).