[Postfix] Allow to set and override a relayhost per mailbox

[Web] Replace recycle icon with trash (this one made me a bit sad)
[Web] Various small fixes
[Web] Allow or disallow a domain admin to change relayhost settings (default is off, as previous default)

data/web/js/site/quarantine.js

@@ -97,7 +97,7 @@ jQuery(function($){
             if (acl_data.login_as === 1) {
             item.action = '<div class="btn-group">' +
               '<a href="#" data-item="' + encodeURI(item.id) + '" class="btn btn-xs btn-info show_qid_info"><i class="bi bi-box-arrow-up-right"></i> ' + lang.show_item + '</a>' +
-              '<a href="#" data-action="delete_selected" data-id="del-single-qitem" data-api-url="delete/qitem" data-item="' + encodeURI(item.id) + '" class="btn btn-xs btn-danger"><i class="bi bi-recycle"></i> ' + lang.remove + '</a>' +
+              '<a href="#" data-action="delete_selected" data-id="del-single-qitem" data-api-url="delete/qitem" data-item="' + encodeURI(item.id) + '" class="btn btn-xs btn-danger"><i class="bi bi-trash"></i> ' + lang.remove + '</a>' +
               '</div>';
             }
             else {