kas-container: Start init service inside container

This helps reaping zombies if processes do not perform proper cleanups.
Known to stumble is bazel so far, see
https://github.com/bazelbuild/bazel/issues/13823. But as the overhead of
an init service is negligible and problems around this are hard to
debug, we better add this option by default.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

kas-container

@@ -342,7 +342,7 @@ set -- "$@" -v "${KAS_REPO_DIR}":/repo:${KAS_REPO_MOUNT_OPT} \
 	-v "${KAS_BUILD_DIR}":/build:rw \
 	--workdir=/repo \
 	-e KAS_BUILD_DIR=/build \
-	-e USER_ID="$(id -u)" -e GROUP_ID="$(id -g)" --rm
+	-e USER_ID="$(id -u)" -e GROUP_ID="$(id -g)" --rm --init
 
 if [ -n "${KAS_SSH_DIR}" ] ; then
 	if [ ! -d "${KAS_SSH_DIR}" ]; then