Add Jenkinsfile for CI
    
    Current nodes of [1] are running in legacy mode and will be removed.
    We need to update related jobs to use new infra.
    See [2] and [3] for more info.
    
    [1] https://jenkins-fedora-infra.apps.ocp.ci.centos.org/job/fedpkg
    [2] https://pagure.io/centos-infra/issue/829
    [3] https://sigs.centos.org/guide/ci/
    
    JIRA: RHELCMP-9801
    
    Signed-off-by: Ondrej Nosek <onosek@redhat.com>