[ENHANCEMENT] Add back `settensor!`

[mtfishman]

Either add back or replace settensor!.

[mtfishman]

Reimplemented as setdenamed!:

ITensorBase.jl/src/abstractitensor.jl

Line 89 in 4b837c2

setdenamed!(a::ITensor, denamed) = (a.parent = denamed)

, which uses the more modern dename[d]/unname[d] terminology in NamedDimsArrays.jl.