KRA: add --setup-kra to ipa-server-install
    
    This patch allows to install KRA on first IPA server in one step using
    ipa-server-install
    
    This option improves containers installation where ipa-server can be
    installed with KRA using one call without need to call docker exec.
    
    Please note the the original `kra.install()` calls in
    ipaserver/install/server/install.py were empty operations as it did
    nothing, so it is safe to move them out from CA block
    
    https://pagure.io/freeipa/issue/6731
    
    Reviewed-By: Jan Cholasta <jcholast@redhat.com>
    Reviewed-By: Tomas Krizek <tkrizek@redhat.com>