Extend job&submit instead of Xjob&x_submit

[vavrines]

These two function names look a bit odd.

job = Xjob(ks, body, fv, vv;
    path = joinpath(@__DIR__, "cylinder"),
    freq = 1,
    fields = (:displacement, :temperature, :damage)
)
ret = x_submit(job, bcst, geo, "T"; ref = ref)