feat(docker): prepare portable images with runtime hotel configuration

src/test/docker-update-harness.sh

@@ -12,6 +12,7 @@ flock() { :; }
 sleep() { :; }
 docker() {
  echo "docker $*" >> "$TEST_DIR/calls"
+ if [ "$1" = pull ] && [ "$SCENARIO" = registry-failure ]; then return 1; fi
  case "$1 ${2:-}" in
   'inspect --format')
    if [ "${@: -1}" = epicnext-cms-app ]; then [ "$SCENARIO" = ci-active ] && echo true; return 0; fi