Add Erudo as bookmarklet for injecting devtools

[RangerMauve]

Adding devtools has been a major TODO to make it possible for folks to author new content and inspect pages from their phone.

Sadly doing this natively is a lot of work since the only browser that has it already doesn't provide easy to use patches.

Instead we can use Eruda which injects javascript into a page which hijacks various APIs to provide a console for us to use.

We can have a bookmarklet in the default list which injects Eruda into a page to make it inspectable.

This won't give us stuff like breakpoints, but it'll at least let us debug stuff and have a basic console.