Fix website about icons rendering pixellated / overfilled with colour

[alexandercyu]

Fixes #155

Removed fa-solid from profile-link.html. Prevents fontawesome icon from rendering overfilled with colour.

Also:

• Upgraded fontawesome to 6.5.2
• Changed fontawesome brand class to use 6.5.2 version

[alexandercyu]

Looks good.

The only other change is that the fa-user isn't rendering now. I think that the fa-user class needs to be accompanied with the fa class as well now or else that icon won't render.

Fixed fa-user icon.

Updated fontawesome classes in scientific committee page to use 6.5.2 version.