Measurements of <it>WH</it> and <it>ZH</it> production in the H -> bb<mml:mo stretchy="false"><overbar></mml:mover> decay channel in <it>pp</it> collisions at 13<mml:mspace width="0.166667em"></mml:mspace>Te<mml:mspace width="0.333333em"></mml:mspace> with the ATLAS detector