Support GPG-keys and default public repositories

[ilia1243]

Based on the thread #473 (comment) it is necessary to assess and implement:

1. Support GPG-keys for services.packages.package_manager.repositories on RHEL-like OS families.
2. Install necessary public repositories by default in public environments:
   • docker-ce
   • Repo holding podman for debian OS families.

Consider extending of prepare.package_manager.configure installation task and services.packages.package_manager section.