Update to FontAweome 7

[cderv]

This is major update to FontAwesome.
See

• https://docs.fontawesome.com/upgrade/whats-changed

LaTeX support would be possible: https://ctan.org/pkg/fontawesome7

Some stuff I noticed for the change that would be "Breaking" is

• Icon will be fixed width now (.fa-fw on all of them) (changelog). So this would change the style in output for users.

• Simpler accessibility (changelog) with now aria-label to use instead of title. Also .sr-only CSS disappeared, but not sure it was used. No breakage but adaptation to make in our filter

• .woff2 is now the only format for webfont. This should not break anything as they were used internally only.

• FA usually try to prevent breakage with backward compatibility so this helps also for us to be more confident

• Same as every version they renamed some icons but they do alias them, so again this should be ok.

Overall, I think this should be ok to do the update, same way as we did when we moved from FA5 to FA6.

However, I am wondering if there is an opportunity to bring some multi version configuration. Something that would allows to use FA7 by default, but still opt-in FA6 is some users needs it.

However, they could also pin the extension to the last version with FA6. The fontawesome extension is just a way to ship the version. So we could also use the major version number as the included fontawesome 🤷‍♂️

Thoughts ?