Add missing Back button to toolbar - SSH keys screen

web/templates/admin/list_key.html

@@ -1,6 +1,7 @@
     <div class="l-center">
       <div class="l-sort clearfix noselect">
         <div class="l-unit-toolbar__buttonstrip">
+            <a class="ui-button cancel" id="btn-back" href="javascript:history.back();"><i class="fas fa-arrow-left status-icon blue"></i> <?=__('Back')?></a>
         <?php
         	 echo '<a href="/add/key/" id="btn-create" class="ui-button cancel" title="'.__('Add SSH Key').'"><i class="fas fa-plus-circle status-icon green"></i>'.__('Add SSH Key').'</a>';
         ?>