Old command registration method was interfering with default commands,
causing only a limited subset of commands to show overall.
This change follows the method the frameworks uses when loading in from a
directory to prevent issues with run/load order.
Changed how the command registration was handled due to complications of
action order found during testing. Now the theme service will resolve
and directly register the command on the Kernel instead of them being
fetched from the ThemeService from within Kernel.
More direct, Seems to work.
Allows someone using the theme system to configure the social driver
before a redirect action occurs, by passing a callback as an additional
param to the theme 'addSocialDriver' method.
