We need to add block config files when everything becomes a block, here we should place at least some default block configuration for the old page variables like page title, action links, tabs, messages, site name, slogan and logo. We may or may not include config for things like the Primary and Secondary menus, it just depends on how that pans out.

Relevant issues:

Convert page elements (title, tabs, actions, messages) into blocks
https://drupal.org/node/507488

Convert site elements (site name, slogan, site logo) into blocks
https://drupal.org/node/1053648

Convert global menus (primary links, secondary links) into blocks
https://drupal.org/node/1869476
