Use merged usr throughout the entire bootstrap

steps/improve/merged_usr.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+# SPDX-FileCopyrightText: 2023 fosslinux <fosslinux@aussies.space>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# Add the rest of the FHS that we will use and is not created pre-boot
+ln -s bin /usr/sbin
+for d in bin lib sbin; do
+    ln -s "usr/${d}" "/${d}" || true # these might exist if rerunning
+done