Hints for massif-visualizer in main

Hints

• asv-screenshot-media-url-not-secure
  org.kde.massif-visualizer.appdata.xml:240 - http://milianw.de/files/massif-visualizer/callgraph.png
  Consider using a secure (HTTPS) URL to reference this screenshot image or video.
• asv-content-rating-missing
  org.kde.massif-visualizer.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.massif-visualizer.appdata.xml:269 - http://milianw.de/files/massif-visualizer/allocators.png
  Consider using a secure (HTTPS) URL to reference this screenshot image or video.
• asv-screenshot-media-url-not-secure
  org.kde.massif-visualizer.appdata.xml:211 - http://milianw.de/files/massif-visualizer/memory-chart.png
  Consider using a secure (HTTPS) URL to reference this screenshot image or video.
• asv-cid-contains-hyphen
  org.kde.massif-visualizer.appdata.xml:3 - org.kde.massif-visualizer.desktop
  The component ID contains a hyphen/minus. Using a hyphen is strongly discouraged, to improve interoperability with other tools such as D-Bus. A good option is to replace any hyphens with underscores (`_`).