Reimplement the vendors mechanism on top of 0.19.0

[prilr]

[github-actions[bot]]

Thank you for contributing to the Leapp project!

Please note that every PR needs to comply with the Leapp Guidelines and must pass all tests in order to be mergeable. If you want to request a review or rebuild a package in copr, you can use following commands as a comment:

• review please @oamg/developers to notify leapp developers of the review request
• /packit copr-build to submit a public copr build using packit

Packit will automatically schedule regression tests for this PR's build and latest upstream leapp build. If you need a different version of leapp from PR#42, use /packit test oamg/leapp#42

To launch regression testing public members of oamg organization can leave the following comment:

• /rerun to schedule basic regression tests using this pr build and latest upstream leapp build as artifacts
• /rerun 42 to schedule basic regression tests using this pr build and leapp*PR42* as artifacts
• /rerun-sst to schedule sst tests using this pr build and latest upstream leapp build as artifacts
• /rerun-sst 42 to schedule sst tests using this pr build and leapp*PR42* as artifacts

Please open ticket in case you experience technical problem with the CI. (RH internal only)

Note: In case there are problems with tests not being triggered automatically on new PR/commit or pending for a long time, please contact leapp-infra.

[andrewlukoshko]

Done in https://github.com/AlmaLinux/leapp-repository/pull/114