toolbox/functions has functions that are specific only to web,
specifically defaultToolbarButtons. This has caused the native
build to attempt to bring in a web dependency which leads to a
build error. The fix for now is splitting web functions from
native functions to resolve the build error.

It got broken while rewriting the Web toolbar in React Toolbox. There is
a problem with the toolbars and how we construct the intialState of the
buttons. The _getInitialState() in the toolbox reducer gets the list of
buttons from interfaceConfig, but in fact interfaceConfig is meant to be
overriden in several very important cases. One of the cases being the
external API, which we use in several projects in production.