Sanitize potential security vulnerabilities from SVG files

Created by: ottok

Here is a pretty good article on the topic: https://kinsta.com/blog/wordpress-svg/#svg-security. It links for more information to https://www.owasp.org/index.php/XML_External_Entity_(XXE)_Processing, https://www.owasp.org/images/0/03/Mario_Heiderich_OWASP_Sweden_The_image_that_called_me.pdf

There is a PHP implementation at https://github.com/darylldoyle/svg-sanitizer.

Maybe Scour could include similar sanitizations?