Octane - add octane layout to reflect component co-location

[jenweber]

In several places throughtout these guides, we show the file paths for components as components/my-component.js and templates/components/my-component.hbs. These references need to be updated to reflect the new structure where both hbs and js files are in components. Since the cli guides are not versioned, we should show both classic and octane layouts.

Here's the page to update: https://cli.emberjs.com/release/advanced-use/project-layouts/

The work on the component generators is part of another separate issue, #134, so just edit the layouts page for this PR.

This work should target master and will be merged with 3.14.