Skylight about:messagepreview Integration

[freshstrangemusic]

Skylight is not strictly speaking a Nimbus tool, but it does deal with a lot of Nimbus recipes. It contains about:messagepreview URLs that have to be copied & pasted into the browser.

We could add an integration with Skylight to replace these with buttons to open a new tab with the URL loaded.

[freshstrangemusic]

This would also need to support decoding the special $l10n objects present in recipes.