Add preview renderers for custom content elements

public/typo3conf/ext/ep_theme/Classes/Exception/ConfigurationMissingException.php

@@ -0,0 +1,6 @@
+<?php
+
+namespace EP\EpTheme\Exception;
+
+class ConfigurationMissingException extends \Exception
+{}

public/typo3conf/ext/ep_theme/Classes/Exception/TemplateFileMissingException.php

@@ -0,0 +1,6 @@
+<?php
+
+namespace EP\EpTheme\Exception;
+
+class TemplateFileMissingException extends \Exception
+{}