Add a "page" example

Problem/Motivation

I was demonstrating SDC to other drupal devs and it was requested that a "page" example be shown so that one could quickly see how a collection of components could be used to build up a page.

Proposed resolution

I'll add a "my-page" component that uses each of the other components. The intention here is to provide a single component that uses the rest.

Remaining tasks

Do that.