Port rules for permutedims

[mzgubic]

We only have the following:

./src/rulesets/Base/nondiff.jl:@non_differentiable permutedims(::AbstractArray{Bool})
./src/rulesets/Base/nondiff.jl:@non_differentiable permutedims(::AbstractArray{Bool}, ::Any)

but we could port the generic permutedims rules from Zygote
https://github.com/FluxML/Zygote.jl/blob/05d0c2ae04f334a2ec61e42decfe1172d0f2e6e8/src/lib/array.jl#L104-L109

---

I ran into this when trying out

julia> gradient(x -> sum(permutedims(x, (:a, :b))), NamedDimsArray{(:a, :b)}(rand(2, 3)))
ERROR: ArgumentError: argument is not a permutation
Stacktrace:
  [1] (::Base.var"#744#746"{Tuple{Symbol, Symbol}, Val{2}})(i::Int64)
    @ Base ./combinatorics.jl:284
  [2] ntuple
    @ ./ntuple.jl:49 [inlined]
  [3] invperm(P::Tuple{Symbol, Symbol})
    @ Base ./combinatorics.jl:278
  [4] macro expansion
    @ ./show.jl:955 [inlined]
  [5] (::Zygote.var"#pb#1963"{Tuple{Symbol, Symbol}})(Δ::FillArrays.Fill{Float64, 2, Tuple{Base.OneTo{Int64}, Base.OneTo{Int64}}})
    @ Zygote ~/JuliaEnvs/PortfolioNets.jl/dev/Zygote/src/lib/array.jl:113
  [6] (::Zygote.var"#2561#back#1964"{Zygote.var"#pb#1963"{Tuple{Symbol, Symbol}}})(Δ::FillArrays.Fill{Float64, 2, Tuple{Base.OneTo{Int64}, Base.OneTo{Int64}}})
    @ Zygote ~/.julia/packages/ZygoteRules/OjfTt/src/adjoint.jl:59
  [7] Pullback
    @ ./REPL[62]:1 [inlined]
  [8] (::typeof(∂(#35)))(Δ::Float64)
    @ Zygote ~/JuliaEnvs/PortfolioNets.jl/dev/Zygote/src/compiler/interface2.jl:0
  [9] (::Zygote.var"#50#51"{typeof(∂(#35))})(Δ::Float64)
    @ Zygote ~/JuliaEnvs/PortfolioNets.jl/dev/Zygote/src/compiler/interface.jl:41
 [10] gradient(f::Function, args::NamedDimsArray{(:a, :b), Float64, 2, Matrix{Float64}})
    @ Zygote ~/JuliaEnvs/PortfolioNets.jl/dev/Zygote/src/compiler/interface.jl:76
 [11] top-level scope
    @ REPL[62]:1

which is a result of invperm((:a, :b)) call inside an @adjoint for permutedims. Fixed it by defining a more specific adjoint, but would be nice to be able to write chainrules (which would mean that permutedims adjoint gets removed from Zygote, since that takes precedence)