Remove field_category_icon in favor of field_font_awesome_icon

Signed-off-by: Joe Whitsitt <joe-whitsitt@uiowa.edu>
Add Font Awesome Variables taxonomy as dependency.

Signed-off-by: Joe Whitsitt <joe-whitsitt@uiowa.edu>
Remove field_category_icon in favor of field_font_awesome_icon. Add Font Awesome Variables taxonomy as dependency.

Signed-off-by: Joe Whitsitt <joe-whitsitt@uiowa.edu>