add basic configuration for 'lb build':

- build an amd64 live system (Debian 10 "Buster")
 - don't install 'recommended' packages
 - enable contrib/non-free sections (required for firmwares)
 - enable stable-backports,security,stable-updates repositories
 - don't include source packages in the build (save space)
 - generate iso-hybrid images suitable for boot from USB
 - enable 'installer' mode allowing to install the live system to a fixed disk
 - install packages required for HTTPS APT sources
 - include binary firwares on the iso image
 - included memtest86+ and win32-loaded on the bootable media

auto/build

@@ -0,0 +1,4 @@
+#!/bin/sh
+set -e
+
+lb build noauto "${@}" 2>&1 | tee build.log

auto/clean

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+lb clean noauto "$@"
+rm -f binary.log prepare.log
+rm -rf	.build/ \
+		config/binary \
+		config/bootstrap \
+		config/build \
+		config/chroot \
+		config/common \
+		config/source

auto/config

@@ -0,0 +1,33 @@
+#!/bin/sh
+# live-build configuration script
+# see 'man lb config'
+
+lb config noauto \
+--apt-recommends false \
+--architectures amd64 \
+--archive-areas 'main contrib non-free' \
+--backports true \
+--security true \
+--updates true \
+--source false \
+--binary-filesystem ext4 \
+--binary-images iso-hybrid \
+--checksums sha256 \
+--clean \
+--debconf-frontend dialog \
+--debian-installer live \
+--debian-installer-distribution buster \
+--debian-installer-gui true \
+--debootstrap-options "--include=apt-transport-https,ca-certificates,openssl" \
+--distribution buster \
+--firmware-binary true \
+--firmware-chroot true \
+--initramfs live-boot \
+--iso-publisher dlc \
+--iso-volume dlc-2.1-rc3 \
+--linux-packages "linux-image linux-headers" \
+--bootappend-live "boot=live config" \
+--memtest memtest86+ \
+--win32-loader true
+
+"${@}"