Add Font Awesome (fixes #5443)

Author: thom

interface/web/themes/default/assets/stylesheets/font-awesome-4.7.0/HELP-US-OUT.txt

@@ -0,0 +1,7 @@
+I hope you love Font Awesome. If you've found it useful, please do me a favor and check out my latest project,
+Fort Awesome (https://fortawesome.com). It makes it easy to put the perfect icons on your website. Choose from our awesome,
+comprehensive icon sets or copy and paste your own.
+
+Please. Check it out.
+
+-Dave Gandy