serve static files may create too big filenames

[takisrs]

A temp filename have to be created (a hashed one?) to avoid the following filename restriction.
Warning: file_put_contents(/var/www/vhosts/example.org/min/static/1550657660/b=system/application/themes/ekdromi/javascripts&f=jquery-3.3.1.min.js,general_scripts.js,bootstrap.min.js,bootstrap-select.min.js,ouibounce.min.js,moment.min.js,daterangepicker.js,jquery.lazyload.min.js,jquery-ui.min.js,datepicker-el.js,popup.js,jquery.easing.min.js,jquery.flexslider-min.js,jquery.colorbox.js,jquery.color.js,jquery.inview.min.js,campaigns.js,home.js,campaigns_ajax.js): failed to open stream: File name too long in /var/www/vhosts/ekdromi.gr/2019.ekdromi.gr/min/static/gen.php on line 134