message: add start scripts for cardhost package.json
diff: "build": "ember build",
  "lint:hbs": "ember-template-lint .",
  "lint:js": "eslint .",
  - "start": "ember serve",
  + "start-prereqs": "docker run -d -p 5432:5432 --rm --name cardstack-pg cardstack/pg-test",
  + "stop-prereqs": "docker stop cardstack-pg",
  + "start": "node ./node_modules/.bin/ember s",
  + "start-hub": "node ./node_modules/.bin/ember hub:start",
  + "start-ember": "HUB_URL=http://localhost:3000 node ./node_modules/.bin/ember s",
  "test": "ember test"
  },
  "devDependencies": {
  