Feature request: Background color to indicate obsoleted add-ons

[davidhedlund]

I think a background color should be used to indicate obsoleted add-ons as I described in https://github.com/mozilla/addons/issues/5314 :

Describe the problem and steps to reproduce it:

Edited my WebExtensions collection.

I discovered that Nano Defender has been removed from addons.mozilla.org, removed add-ons should be indicated with a pink background when I edit my collection so I can maintain them properly.

What happened?

What did you expect to happen?

┆Issue is synchronized with this Jira Task