Eliminate warnings and errors due to library item text (name and desctiption) being localized components instead of simply a string. Some are not localized (e.g. LEGO EV3), so either string or component is possible.

Convert `extensions/index` to jsx and use react-intl to define/translate names and descriptions.

Question, should ‘x’ and ‘y’ be localizable?

Push to history when the library mounts. Whenever popstate occurs after mounting, request to be closed.

Behavior captured in the `Modal` container. If we want to re-use this functionality for anything else that uses `ModalComponent`, just use the `Modal` container rather than `ModalComponent`.

* Add coming soon extensions to the library

This implements #1074

* don’t call `onSelect` when disabled

thanks @paulkaplan!

* add speech image to coming soon extension

With locally loaded png image

Alphabetize all the things