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/golden/expected/host-exec.txt

@@ -0,0 +1,5 @@
+docker --log-level=error compose --ansi=auto -f @WD@/stack/host/consul.yml -f @MYOS@/stack/myos/networks.yml -p testhost exec -T consul sh -c consul members
+/bin/bash: -c: line 0: syntax error near unexpected token `||'
+/bin/bash: -c: line 0: `|| true'
+make: *** [exec] Error 2
+[exit 2]