Add spacing to pager component

I wasn't sure about this so adding it as a separate MR. On listing pages with a pager, in the designs the pager has padding above and below it. If this isn't added at the pager component level then it would need to be wrapped in an extra div in a Drupal template and have the spacing applied there. I realise that on the whole we don't add spacing to components but this one seems like it should always have it's own spacing applied. Note that this spacing on the pager is in addition to the flow spacing applied in the level above.