feat: support scoped bundle names

[lennyburdette]

When using an engine in a package called "@lennyburdette/my-engine", I would like to keep the following strings consistent:

• The package name (for ember install @lennyburdette/my-engine).
• The addon/engine name in index.js (for this.mount('@lennyburdette/my-engine', { path: 'my-engine' }).
• The module prefix in config/environment (for import Foo from '@lennyburdette/my-engine').

Currently, ember-asset-loader generates the asset manifest using only the scope, not the full package name. This change detects package scopes and only generates bundles with full package names.

[lennyburdette]

@rwjblue @trentmwillis Looks like I could use some help getting tests to pass here.

It appears that master started failing when jquery 3.3 was released:
https://travis-ci.org/ember-engines/ember-asset-loader/builds
https://blog.jquery.com/2018/01/19/jquery-3-3-0-a-fragrant-bouquet-of-deprecations-and-is-that-a-new-feature/

There's a note on the jquery release post that they are no longer testing in phantomjs 1.9. Should this project also drop support for that version?

The other failure is a node test exceeding the two second test timeout. This may be due to my changes, but I don't think so. The failing test is the first to use verifyInsertedManifest, which spins up a broccoli builder. I'm assuming the next two tests are able to take advantage of a broccoli cache so they're a bit faster. Is it reasonable to assume that a broccoli builder could take longer that 2000ms on an underpowered travis vm?

[rwjblue]

Thanks for fixing CI in #66! Now that things are in order, we can start moving forward here...

[rwjblue]

I really like splitting this out into a stand alone function, which should make testing various combinations much easier. Can you export this function privately, and add some unit tests around expected inputs and outputs?

[lennyburdette]

Good idea! Adding tests gave me an opportunity to clean up some quirks that carried over from the original implementation.

[rwjblue]

Awesome thank you!