Hints for gnome-usage in main

Hints

• asv-summary-has-dot-suffix
  org.gnome.Usage.appdata.xml:65 - Elegantní způsob, jak zobrazit informace o využití systémových prostředků.
  The component summary should not end with a dot (`.`).
• asv-nonstandard-gnome-extension
  org.gnome.Usage.appdata.xml:128 - kudos
  This tag is a GNOME-specific extension to AppStream and not part of the official specification. Do not expect it to work in all implementations and in all software centers.
• asv-content-rating-missing
  org.gnome.Usage.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-url-not-secure
  org.gnome.Usage.appdata.xml:137 - http://www.gnome.org/friends/
  Consider using a secure (HTTPS) URL for this web link.