Replacing Font-Awesome Icons on Wiki Pages

This MR replaces both usecases of the fa-cloud-download icon. It falls back to use the glui download icon, as we don't have a cloud download version.

Replacements:

On the wiki pages side, we now have the download next to clone, and I also replaced the chevron one as it was in the same file.

Also replaced the icon in the wiki sidebar

Closes #225894 (closed)