hey_germano's sandbox: Test Entity Flag

The problem

Creating test content is a standard part of developing a new site, but removing all of that test content before launch can be error-prone and tedious, especially once you've added some real content.

The fix

This module adds a checkbox to entities which allows content creators to flag the entity as test content. It also provides an admin UI which can be used to bulk unflag or delete test content items.

D8 port

In-progress! See https://www.drupal.org/node/2910264.