Cleanup Google Font and Font awesome Usage

The ASF blocks requests to external domains via CSP, by default.

The correct way to address the following would be to add the files to our repo and update the references across the site to point to our copies.

https://grails.apache.org/docs/latest/grails-data/hibernate5/manual/index.html

https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700

https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css