Support Entity Clone module

Problem/Motivation

At the moment this module depends on Quick Node Clone module, therefor it is only possible to create the template for node. It would be nice to move all quick node clone module related features to submodule and create another submodule that supports entity clone https://www.drupal.org/project/entity_clone . The template entity class and everything related should stay in the "main" content_template module.

Remaining tasks

Create new submodule that supports entity_clone module.
Create an update hook to enable quick_node_clone submodule for existing installations.
Hide the main module from Modules list, because on its own it is not doing much, leave only submodules.