include Katello in GHA tests

Bump actions/upload-artifact from 3 to 4

• Bump actions/upload-artifact from 3 to 4

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 3 to 4.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](https://github.com/actions/upload-artifact/compare/v3...v4)...

Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](https://github.com/actions/cache/compare/v3...v4)...

run external kickstart and grub tests on GHA

also execute assets:precompile as part of GHA tests

execute db:seed as a test

run integration tests as part of the GHA matrix

enable GHA for pushes to develop and stable branches

without this there is never a "base" cache and PRs always start off
without any cached gems, taking longer to execute

move rubocop into foreman.yml

configure cancel-in-progress for new foreman workflow

parallelize tests on GHA

Fixes #36913 - Set up GHA with matrix to run test on Ruby 2.7

Co-Authored-by: Ewoud Kohl van Wijngaarden <ewoud@kohlvanwijngaarden.nl>
Co-Authored-by: Evgeni Golov <evgeni@golov.de>