Give the `Everything` sub category an image that represents everything

[Pjaerr]

Currently on the category selection screen the SubCategory Everything doesn't have an image like the rest of the sub categories.

The images for a sub category are pulled in from the \frontend\static\category-images folder and the image file name must match. The image is pulled through the SubCategory component like so:

<Styled.SubCategoryListItem
      showImage={showImage}
      image={`/static/category-images/${query.replace(' ', '_')}.jpg`}
    >

This will need changing so that showImage is true and the image points to a relative image.