2 directories called "extensions"

During my first 3.0 install I was confused at first that Bolt first told me that I should chmod my **extensions** directory, just after I already did so - or so I thought.

Of course, more careful reading revealed that there's 2 **extensions** directories on different paths.

Without knowing what technical consequences this may have, I suggest naming one of those 2 directories differently if still possible to avoid confusion by sloppy readers. The public one seems the best candidate for renaming to something descriptive like **extensions-config** or **config-extensions**.