Release 3.1.9

[andrey-utkin]

Planned PRs/issues/features:

• Orderly shutdown upon SIGTERM
• faster building and testing. v3.1.8 takes up to 40 minutes to build for all distros, and then 90 minutes to run tests on all distros, breaks the thinking flow a lot
  • leverage github actions
  • separate own ffmpeg packages, it changes very rarely (but we do need our own build)
  • build scripts and procedures optimization
  • build for one distro, start testing this build, meanwhile a package for another distro is being built. Currently it's "buildall && testall"
  • caching containers
    • installer updated -> save resulting container for updated build installs & testing
    • release build updated -> save container for testing
• Stop repeating root crontab cleaning code on upgrade https://forums.bluecherrydvr.com/t/server-upgrade-is-deleting-lines-from-root-crontab/968/2
• When device_state notif mailer is called, empty users email field causes stacktrace in server logs #720

Previous release: #713