Subsume the useful bits of the apertis-customizazions package in the recipes

Most of the bits in the apertis-customizazions package come from a time before the move to Debos and with the recent rebase to Buster it became apparent that some are no longer needed:

• sudoers.d/apertis-customizations: Disables fqdn resolution in sudo, libnss-myhostname makes that unneeded
• systemd/system/etc.mount: can be dropped, a read-only /etc doesn't add much
• systemd/system/run-user.mount: /runis a tmpfs,/run/user/$UIDis another tmpfs, mounting a tmpfs on/run/user` is not needed
• systemd/system/var.mount: was probably meant to mount /var as read-only but uses bind instead of rbind so it was effectively read-write anyway
• systemd/system/etc-rw.service: Made obsolete by dropping etc.mount
• systemd/system/var-rw.service: Switching /var to rw was in fact a no-op
• udev-rules.d/60-apertis-customizations.rules: unneeded on the public recipes, see APERTIS-5749
• systemd/system/tmp.mount: should be made a default in the systemd package, Debian doesn't do it due to backward compatibilty concerns that do not affects us, see APERTIS-5750

The useful bits:

• systemd/system/media.mount: mounting a tmpfs on /media still seems sensible to reduce the flash wear
• systemd/system/apertis-create-homedir.service: we still rely on the lazy homedir creation
• sbin/apertis-create-homedir-if-needed: see above
• sbin/apertis-dev: we still need to be able to switch to GPLv3 tools for development purposes
• tmpfiles.d/apertis.conf: systemd now generates an unique machine-id if /etc/machine-id exists but it is empty

overlays/apertis-dev/sbin/apertis-dev

+#!/bin/sh
+
+# Copyright © 2015 Collabora Ltd.
+#
+# SPDX-License-Identifier: MPL-2.0
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Reconfigure an Apertis target system for debugging and basic development.
+
+set -e
+
+die () {
+    echo "$0: $@" >&2
+    exit 1
+}
+
+packages="openssh-server rsync"
+build=
+build_dep=""
+gpl3=
+enable_debug=
+disable_debug=
+
+while [ "$#" -gt 0 ]; do
+    case "$1" in
+        (--help)
+            echo "usage: sudo apertis-dev [OPTIONS]"
+            echo "Enable debugging and basic development."
+            echo "OPTIONS are:"
+            echo "    -b|--build: install basic build tools"
+            echo "    -d|--build-dep PACKAGE: install build-deps of PACKAGE"
+            echo "    -g|--debug: install basic debugging tools"
+            echo "    -3|--gpl3: install GPL3 versions of tar, coreutils"
+            echo "    --enable-debug: enable debug logging from applications"
+            echo "    --disable-debug: disable debug logging from applications"
+            echo "For developer use only: do not do this in production."
+            exit 0
+            ;;
+        (-b|--build)
+            build=1
+            shift
+            ;;
+        (-d|--build-dep)
+            build=1
+            build_dep="$build_dep $2"
+            shift 2
+            ;;
+        (-g|--debug)
+            # devscripts is mainly here so we have debi
+            packages="$packages apertis-tests devscripts gdb strace valgrind bash-completion less systemd-coredump"
+            shift
+            ;;
+        (-3|--gpl3)
+            gpl3=1
+            shift
+            ;;
+        (--enable-debug)
+            enable_debug=1
+            shift
+            ;;
+        (--disable-debug)
+            disable_debug=1
+            shift
+            ;;
+        (*)
+            die "unknown option \"$1\""
+            ;;
+    esac
+done
+
+[ "$(id -u)" = 0 ] || die "must be run as root"
+
+if [ -n "$enable_debug" ] && [ -n "$disable_debug" ]; then
+    echo "Both --enable-debug and --disable-debug specified. Doing neither."
+    enable_debug=
+    disable_debug=
+fi
+
+if [ -n "$build" ]; then
+    packages="$packages build-essential ccache devscripts fakeroot"
+    packages="$packages pristine-tar python3-debian"
+fi
+
+mount -o remount,rw /
+# replace "target" component with "development" unless "development" is
+# already there
+sed -i.orig -e '/\bdevelopment\b/! s/ target\( \|$\)/ target development\1/' /etc/apt/sources.list
+apt update
+apt-get -y install --no-install-recommends eatmydata
+eatmydata apt-get -y install --no-install-recommends $packages
+if [ -n "$build_dep" ]; then
+    eatmydata apt-get -y build-dep --no-install-recommends $build_dep
+fi
+
+if [ -n "$gpl3" ]; then
+    # Workaround for https://bugs.apertis.org/show_bug.cgi?id=626
+    # dpkg will fail if there isn't a tar and an rm on $PATH
+    cp /bin/rm /bin/tar /usr/local/bin
+    apt-get -y install coreutils tar
+    rm /usr/local/bin/rm /usr/local/bin/tar
+fi
+
+if [ -n "$enable_debug" ]; then
+    # Enable debug logging for Canterbury and all the applications it spawns.
+    mkdir -p /etc/systemd/user/canterbury.service.d
+    cat << EOF > /etc/systemd/user/canterbury.service.d/apertis-dev.conf
+[Service]
+Environment=G_MESSAGES_DEBUG=all
+EOF
+    echo "Wrote /etc/systemd/user/canterbury.service.d/apertis-dev.conf"
+fi
+
+if [ -n "$disable_debug" ]; then
+    # Undo what --enable-debug does.
+    rm /etc/systemd/user/canterbury.service.d/apertis-dev.conf
+    echo "Deleted /etc/systemd/user/canterbury.service.d/apertis-dev.conf"
+fi
+
+if [ -n "$enable_debug" ] || [ -n "$disable_debug" ]; then
+    # The user needs to run `systemctl --user daemon-reload` and restart Canterbury,
+    # but restarting Canterbury by itself will probably produce weird state; so just
+    # advise to restart the system.
+    echo "*** Now reboot the system, or stop and restart the SDK simulator."
+fi
+
+# vim:set sw=4 sts=4 et: