check all APKs for old versions of OpenSSL

This scans all APKs for old versions of OpenSSL libraries that are known to
be vulnerable to issues, or fully unsupported.

This really should be implemented as a per-APK AntiFeature, so that it can
apply to any version that is vulnerable.  Since AntiFeatures are currently
only per-App, this instead sets the AntiFeature only if the latest APK is
vulnerable.

Google also enforces this:
https://support.google.com/faqs/answer/6376725?hl=en