feat: use styles of wrap plugin by default

The wrap plugin's styles are sufficiently simple that mpdf can handle
them. Also the print-styles of wrap are very bland, which constitutes a
great loss for a plugin with a main focus of colorful styling. Finally
the wrap plugin is widely spread, hence many users will benefit from
this.

Author: micgro42

conf/default.php

@@ -9,6 +9,6 @@
 $conf['template']         = 'default';
 $conf['output']           = 'file';
 $conf['usecache']         = 1;
-$conf['usestyles']        = '';
+$conf['usestyles']        = 'wrap,';
 $conf['qrcodesize']       = '120x120';
 $conf['showexportbutton'] = 1;