Hints for imagination in main

Hints

• asv-content-rating-missing
  net.sf.imagination.imagination.metainfo.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
  net.sf.imagination.imagination.metainfo.xml:52 - http://imagination.sourceforge.net/screenshots/transitions_types.png
  Consider using a secure (HTTPS) URL to reference this screenshot image or video.
• asv-screenshot-media-url-not-secure
  net.sf.imagination.imagination.metainfo.xml:48 - http://imagination.sourceforge.net/screenshots/heart-in.png
  Consider using a secure (HTTPS) URL to reference this screenshot image or video.
• asv-screenshot-media-url-not-secure
  net.sf.imagination.imagination.metainfo.xml:56 - http://imagination.sourceforge.net/screenshots/exporting.png
  Consider using a secure (HTTPS) URL to reference this screenshot image or video.