Migrate dirinstall gating test from STI to TMT
The Fedora rawhide CI tests are used.
This pull request enables tests in the RHEL gating using `tmt` which
also allows to easily execute and debug tests from your laptop:
Run tests directly on your localhost:
sudo dnf install -y tmt
tmt run --all provision --how local
Run tests in a virtual machine:
sudo dnf install -y tmt-provision-virtual
tmt run
Check the documentation to learn more about the tool:
https://docs.fedoraproject.org/en-US/ci/tmt/
Related: rhbz#2006718