Rework build system further

- Move everything related to base/ into that directory, including Containerfile
- Introduce `bootc-base-image-rebuild-self` that can be used to
  resynthesize the base image, and it has docs.
- Rework the standard image to put its build instructions in
  usr/share/doc/bootc-image-standard to serve as a reference

Signed-off-by: Colin Walters <walters@verbum.org>

Containerfile

@@ -1,42 +1,18 @@
-# This generates the default base image.
+# This generates the "standard" base image, deriving from the minimal base.
 
 # This is a local reference by default because we haven't shipped this image yet.
 FROM localhost/fedora-bootc:base
-# Drop our package sets into /usr/share/doc, so that other things can parse it
-COPY packages*.txt /usr/share/doc/fedora-bootc/
-# Overlay our defaults
+# Copy in our configuration and build scripts. Most of the heavy lifting
+# is in `stage-install` which we emit into /usr/share/doc so it can be
+# used as a reference in other images.
 COPY usr/ /usr/
 RUN <<EORUN
-set -euo pipefail
-dnf_args=()
-echo "Loading packages-excluded"
-basedir=/usr/share/doc/fedora-bootc/
-for x in $(grep -E -v '^#' ${basedir}/packages-excluded.txt); do
-  dnf_args+=(--exclude ${x})
-done
-echo "Loading packages"
-package_files=(${basedir}/packages-recommended-minimal.txt ${basedir}/packages.txt)
-pkgfile_for_arch=/usr/share/doc/fedora-bootc/packages-$(arch).txt
-if test -f ${pkgfile_for_arch}; then
-  echo "Loading ${pkgfile_for_arch}"
-  package_files+=(${pkgfile_for_arch})
-fi
-base_pkgs=$(grep -hE -v '^#' ${package_files[@]})
-dnf -y ${dnf_args[@]} install $base_pkgs
-
-# Ensure we regenerate the initramfs with new content
-# https://docs.fedoraproject.org/en-US/bootc/initramfs/
-kver=$(cd /usr/lib/modules && echo *); dracut -vf /usr/lib/modules/$kver/initramfs.img $kver
-
-# Undo RPM scripts enabling units; we want the presets to be canonical for the base image.
-# https://github.com/projectatomic/rpm-ostree/issues/1803
-rm -rf /etc/systemd/system/*
-systemctl preset-all
-rm -rf /etc/systemd/user/*
-systemctl --user --global preset-all
-
-dnf clean all
-# Lots of cleaning
-rm -vrf /var/log /var/cache /var/lib/dnf
+set -xeuo pipefail
+# This script installs our default packages. These scripts
+# are not a stable API, but may become one in the future.
+/usr/share/doc/bootc-image-standard/stage-install
+# Cleanup
+/usr/share/doc/bootc-image-standard/stage-clean
+# And lint.
 bootc container lint
 EORUN