Migrate docs site from pods to normal layout w/ colocated components

[maxfierke]

The tests/dummy app that powers the docs site is still using pods and it would be great to get it onto a more supported Ember layout

Ideally, we could keep some of the nice component organization of pods, using component colocation, but without the downsides of pods (somewhat unsupported, everything being called "component.{js,hbs}")

[maxfierke]

This will actually need to be a v3 thing, since we'll need to drop Ember < 3.13 support to use colocation

[ijlee2]

When it's time for v3.0 development, I recommend using ember-codemod-pod-to-octane to un-pod the demo app.

# If the current directory is the addon root
npx ember-codemod-pod-to-octane --type=app --root=tests/dummy

The codemod takes care of moving files to the correct places.

After running the codemod, the contributor would manually check and fix references to, or from, the moved files (e.g. import statements), if there are any.