nixos/networkmanager: add doc about nm profiles interaction with resolvconf

            And if you edit a declarative profile NetworkManager will move it to the persistent storage and treat it like a ad-hoc one,

            but there will be two profiles as soon as the systemd unit from this option runs again which can be confusing since NetworkManager tools will start displaying two profiles with the same name and probably a bit different settings depending on what you edited.

            A profile won't be deleted even if it's removed from the config until the system reboots because that's when NetworkManager clears it's temp directory.

            If `networking.resolvconf.enable` is true, attributes affecting the name resolution (such as `ignore-auto-dns`) may not end up changing `/etc/resolv.conf` as expected when other name services (for example `networking.dhcpcd`) are enabled. Run `resolvconf -l` in the terminal to see what each service produces.

          '';

        };

        environmentFiles = mkOption {