all: Use ->remove() instead of ->outertext = ''

simplehtmldom 1.9 introduced new functions to recursively remove
nodes from the DOM. This allows removing elements without the need
to re-load the document by using $html->load($html->save()), which
is very inefficient.

Find more information about remove() at
https://simplehtmldom.sourceforge.io/docs/1.9/api/simple_html_dom_node/remove/

bridges/CastorusBridge.php

@@ -58,7 +58,7 @@ class CastorusBridge extends BridgeAbstract {
 			returnServerError('Cannot find nodes!');
 
 		foreach($nodes as $node) {
-			$node->outertext = '';
+			$node->remove();
 		}
 
 		return strtotime($activity->innertext);