Option+double click to open .app bundles and .AppDirs

Right now we have to right-click, then "Open in new Tab" to see the contents of `.app` bundles and `.AppDir`s. This is too complicated.

Bruce Tognazzini:

> In fact, I proposed it way back in 1985
>
> clicking, dragging, and double-clicking a package would do exactly what these actions normally do. Only by option-double-clicking would the interior of the object be displayed. The purpose of that was to keep novices from accidentally rooting around in there, damaging things.

https://www.asktog.com/readerMail/1999-11ReaderMail.html#Anchor7

> Bruce Tognazzini was hired at Apple by Steve Jobs and Jef Raskin in 1978, where he remained for 14 years, founding the Apple Human Interface Group. He remains a major Apple fan, which is why, when they could do better, he feels compelled to talk about it.

https://www.asktog.com/columns/079BentoSchmento.html