Summary

We still use everywhere (sharing buttons, footer icons) the Twitter logo but now that it's not Twitter any more. We should swap it with the X one.

Requirements

• Use the SVG attached as the icon for X
• On footer, we use the name/css-class x-twitter on footer menu to make it appear. And follow the same color (and hover) as other icons there.
• On share buttons, we should use black color for the icon.