Enable the edit pencil for this app

[jenweber]

In the guides, we have an edit pencil at the top of each page. This helps contributors participate. We'd like to add that to this app.

This feature is already supported, and I think we just need to configure it.

[sdahlbac]

I started looking at this, but I suspect that the functionality you are talking about is:

https://github.com/empress/guidemaker/blob/3c2fb9e3dac0764a36ea617d970e828aa62a52ba/README.md?plain=1#L85
and used here:
https://github.com/ember-learn/guidemaker-ember-template/search?q=sourceRepo

but as far as I can tell, the deprecation-app is not using the guidemaker nor the guidemaker-ember-template.

So, is the right course of action to copy in the functionality from there, or pull in guidemaker et al?

[sdahlbac]

@jenweber what is your take?