Add template suggestions for node.html.twig based on the view mode

Before:

<!-- THEME DEBUG -->
<!-- CALL: _theme('node') -->
<!-- FILE NAME SUGGESTIONS:
   * node--1.html.twig
   * node--article.html.twig
   x node.html.twig
-->
<!-- BEGIN OUTPUT from 'core/themes/bartik/templates/node.html.twig' -->

After:

<!-- THEME DEBUG -->
<!-- CALL: _theme('node') -->
<!-- FILE NAME SUGGESTIONS:
   * node--1.html.twig
   * node--article--full.html.twig
   * node--full.html.twig
   * node--article.html.twig
   x node.html.twig
-->
<!-- BEGIN OUTPUT from 'core/themes/bartik/templates/node.html.twig' -->

The ordering is definitely up for debate, I can see maybe swapping --article and --full. Note that twig_debug output shows the suggestions from most specific to least specific.

Oops, duplicate of #1503464: Automatically add theme hook suggestion for node view mode.