Revert "Issue #1852966 by yched, swentel: Rework entity display settings around EntityDisplay config entity."

This reverts commit 8ad67af2.

Issue #1852966 by yched, swentel: Rework entity display settings around EntityDisplay config entity.

Issue #1552396 by andypost, sun, tim.plunkett, amateescu, YesCT: Convert vocabularies into configuration.

Issue #1831324 by sun, effulgentsia: Form API #autocomplete_path() JS and callbacks to use GET q= parameter instead of menu tail.

Issue #1241938 by swentel, Niklas Fiekas, yched: Added support for #placeholder to relevant Field API widgets.

Issue #1754070 by tim.plunkett, dead_arm: Fixed Editing and re-saving a node with tagged taxonomy terms removes terms from node.

Issue #1619446 by Niklas Fiekas: Fixed All autocomplete and drupal_json_output() responses are broken (returning Ajax instead of JSON).