Hints for kaffeine in main

Hints

• asv-url-not-secure
  org.kde.kaffeine.appdata.xml:113 - http://kaffeine.kde.org
  Consider using a secure (HTTPS) URL for this web link.
• asv-content-rating-missing
  org.kde.kaffeine.appdata.xml -
  This component has no `content_rating` tag to provide age rating information. You can generate the tag data online by answering a few questions at https://hughsie.github.io/oars/
• asv-screenshot-media-url-not-secure
  org.kde.kaffeine.appdata.xml:140 - http://kde.org/images/screenshots/kaffeine.png
  Consider using a secure (HTTPS) URL to reference this screenshot image or video.