Figure how to get rid of v1 addon / go full native JS

[NullVoxPopuli]

Today, ember-scoped-css is a v1 addon (with some v2esque things)
The advantage of the v1 addon is that it auto-installs itself, configures babel, and dumps all the CSS generated by it in to the vendor.css.

To migrate to a v2 addon, we'd want some structure like this:

• ember-scoped-css
  • runtime/
    • allows importing of the scopedClass helper
  • buildtime/
    • requires adding a babel plugin to your babel config
    • requires adding a webpack/unplugin plugin to put the generated CSS in the app's dist

new package: ember-scoped-css-compat

• uses ember-scoped-css to do v1 things like auto-installing

[mattmcmanus]

[NullVoxPopuli]

This was done in #50
and released in 0.11.0