Use Composer Manager by default for Drupal 8

[grayside]

Drupal 8 modules sometimes have composer dependencies. As an intermediary step towards phase2/grunt-drupal-tasks#212, we should have out-of-box support for Composer Manager, and a 2-step composer install process.

• Customize the build process to run composer manager & composer install in the docroot after drush make & scaffold is complete.
• Research whether we can stash the lockfile somewhere else, say composer-drupal8.lock at the project root.

Example Script Invocation

"composer-manager": "cd <%= config.buildPaths.html %> && php ./modules/contrib/composer_manager/scripts/init.php && composer drupal-rebuild && composer update --lock && cd -",

[grayside]

Nope.