Release 0.309 checklist

This is a tracking issue for what I think we need to accomplish for release 0.309, ideally.

• Merge #3753 (One outstanding comment currently for Michael, Troy plans to review)
• Merge #3772 (see comments) either through the installer or creating an AppArmor profile
• Merge #3755 (Give me ability to update MediaWiki)
• Merge #3766 (Make it possible to detect if a grain is running on Classic, Tempest, null (Kenton's version), etc.)
• Merge #3757 (Migration script for moving to our build)
• Merge #3779 (Release GPG key)
• Merge #3784 (Use GPG key for update verification)