Add build_name metadata to build.info file for OCI and Base images

Presence of this field helps in determining if the image is an
unminimized image, which then can be leveraged in the unminimize
script to easily determine the image type.

live-build/auto/build

@@ -430,9 +430,16 @@ serial: $BUILDSTAMP
 EOF
 		fi
 
-		if [ "$PROJECT" = "ubuntu-oci" ]; then
+		if [ "${PROJECT}" = ubuntu-base ] || [ "${PROJECT}" = "ubuntu-oci" ]; then
 			if [ -n "$BUILDSTAMP" ]; then
-				configure_oci chroot "$BUILDSTAMP"
+				mkdir -p chroot/etc/cloud
+				cat > chroot/etc/cloud/build.info << EOF
+build_name: $PROJECT:${SUBPROJECT:}
+serial: $BUILDSTAMP
+EOF
+				if [ "${PROJECT}" = "ubuntu-oci" ]; then
+					configure_oci chroot "$BUILDSTAMP"
+				fi
 			else
 				echo "The \$BUILDSTAMP variable is empty"
 				exit 1

live-build/functions

@@ -970,13 +970,6 @@ configure_oci() {
     Chroot ${chroot} "chmod +x /usr/sbin/policy-rc.d"
 
 
-    # Inject a build stamp into the image
-    mkdir -p ${chroot}/etc/cloud
-    cat > ${chroot}/etc/cloud/build.info << EOF
-serial: $serial
-EOF
-
-
     # https://github.com/docker/docker/blob/9a9fc01af8fb5d98b8eec0740716226fadb3735c/contrib/mkimage/debootstrap#L54-L56
     Chroot ${chroot} "dpkg-divert --local --rename --add /sbin/initctl"
     cp -a ${chroot}/usr/sbin/policy-rc.d ${chroot}/sbin/initctl