package.json "type": "module" testing for embroider and ember-auto-import

See: embroider-build/embroider#1773

Creating new scenarios

./create-scenario.sh "name-of-thing"

This'll create a library, and a few apps with varying configs to test against.

Post script todos (automated):

• add "type": "module" to the library's package.json.
• add --test-port 0 to the apps test:ember script

Each example library has its own set of apps to test with, because sometimes type=module crashes the whole app.