nixos/systemd: add upstream units for boot counting (#436893)

Changed files
+4
nixos
modules
system
+4
nixos/modules/system/boot/systemd.nix
···
"systemd-rfkill.service"
"systemd-rfkill.socket"
+
# Boot counting
+
"boot-complete.target"
+
"systemd-bless-boot.service"
+
# Hibernate / suspend.
"hibernate.target"
"suspend.target"