Rework screens for disabled extensions to be more enticing

[anbuzin]

At the moment, whenever the user clicks on an extension tab when that extension is not enabled in the schema, they are greeted with this concise message:

This real estate could be better used to compel the user to enable the extension by showing the value they could get from it.

[anbuzin]

@1st1, @beerose, @scotttrinh please have a look and share your ideas.