gen_conf: Use UUID for non-name-ref parent

If parent interface is not referenced by interface name, in `gen_conf`
mode, nmstate cannot tell the real interface name of parent, so child
should refer its parent by UUID.

Implementation detail:
    In `gen_conf` mode, the UUID of certain interface can be predict by
    its name and type, so instead of modify the generated NmConnection
    afterwards, this patch invoke `Interface.change_parent_name()` to
    change the parent name into `UUID` of its parent when its parent is
    non-name identifier.

Integration test cases included for all child interface types matched by
MAC address:
 * VLAN
 * VxLAN
 * MAC VTAP
 * MAC VLAN
 * MAC Sec

Resolves: https://issues.redhat.com/browse/RHEL-94783

Signed-off-by: Gris Ge <fge@redhat.com>