security: Display security info for apps

From a discussion with @federico, here is some security information that we can display for each app:

• if the app has been sandboxed
• how effective is the sandboxing, some alternatives:
  • if the sandboxing features have been reviewed
  • a count or score based on sandboxing features
  • badges or medals to indicate the sandboxing features in use
• a count of past cves
• a count of current cves (using debsecan #1609 (closed))

This is to help the user understand if there is a risk when using the app. This is especially useful for packages installed from backports, as backports does not have the same level of security support (https://backports.debian.org/FAQ/).