add shellspec golden harness for the legacy make engine

- spec/golden/cases.txt: 69 black-box cases (CLI wrapper mode and make
  include mode) run in a hermetic sandbox with a mocked docker
- spec/golden/expected/*.txt recorded from this engine (baseline)
- make test / test-golden / golden-record / lint dev targets

spec/fixtures/host-project/stack/host/consul.yml

@@ -0,0 +1,12 @@
+services:
+  consul:
+    image: hashicorp/consul:1.15
+    container_name: ${HOST_COMPOSE_PROJECT_NAME:-localhost}-consul
+    network_mode: host
+    restart: always
+    environment:
+      CONSUL_HTTP_TOKEN: ${HOST_CONSUL_HTTP_TOKEN}
+    volumes:
+      - consul:/consul/data
+volumes:
+  consul: