move simple enhancer config into json file

cc @icewind1991 @phedlund @David-Development 

@bastei can you add themerepublic.net and check why it throws 

```
<b>Warning</b>:  OCA\News\Utility\ArticleEnhancer\ArticleEnhancer::substituteRelativeLinks(): unterminated entity reference callback=related_results_labels_thumbs&amp;max-results=7 in <b>/srv/http/news/utility/articleenhancer/articleenhancer.php</b> on line <b>124</b><br />
```