[NDTensors] [ENHANCEMENT] Support similartype(Matrix{Float64}, Val(3))

[mtfishman]

One can do:

julia> similartype(Matrix{Float64}, (2, 2, 2))
Array{Float64, 3}

but it would be nice to have something in the type domain, like:

julia> similartype(Matrix{Float64}, Val(3))

or a more specific type than Val, like NDims:

julia> similartype(Matrix{Float64}, NDims(3))

related to the proposal for basing similar around traits here: JuliaLang/julia#18161.