* Introduce prepare-env command to setup the env according to one option set generated by generate-ci-jobs. This allows us to hide this implementation logic and simplify CI config files. This works for now only on GitHub Actions.
* Start implementing support for repositories with multiple version for one recipe and for repositories with multiple recipes with multiple versions (like CCI). This works so for for Installers, header_only recipes and the Linux configurations for any other packages while running on GitHub Actions. There is not yet any support for other CI systems.