systemd: 254.6 -> 255.2

Removed patches:

- 0007-Fix-hwdb-paths.patch

  The directory we want seems to already be included in the list. Is there
  a reason why we want to restrict it further?

- 0010-build-don-t-create-statedir-and-don-t-touch-prefixdi.patch

  This patch has little to do with how the meson.build file looks now. The
  new patch 0017 is the successor to this one.

- 0015-pkg-config-derive-prefix-from-prefix.patch

  This is fixed upstream. We don't need this anymore.

nixos/modules/system/boot/systemd/initrd.nix

@@ -70,6 +70,7 @@ let
     "systemd-tmpfiles-setup.service"
     "timers.target"
     "umount.target"
+    "systemd-bsod.service"
   ] ++ cfg.additionalUpstreamUnits;
 
   upstreamWants = [
@@ -424,6 +425,7 @@ in {
 
       storePaths = [
         # systemd tooling
+        "${cfg.package}/lib/systemd/systemd-executor"
         "${cfg.package}/lib/systemd/systemd-fsck"
         "${cfg.package}/lib/systemd/systemd-hibernate-resume"
         "${cfg.package}/lib/systemd/systemd-journald"
@@ -433,6 +435,7 @@ in {
         "${cfg.package}/lib/systemd/systemd-shutdown"
         "${cfg.package}/lib/systemd/systemd-sulogin-shell"
         "${cfg.package}/lib/systemd/systemd-sysctl"
+        "${cfg.package}/lib/systemd/systemd-bsod"
 
         # generators
         "${cfg.package}/lib/systemd/system-generators/systemd-debug-generator"