Inplace Chebyshev transform

[jishnub]

These are supported by FastTransforms, so we may add these here. After this, the following works:

julia> v = rand(10);

julia> v2 = copy(v);

julia> transform!(Chebyshev(), v);

julia> transform(Chebyshev(), v2) == v
true

[codecov]

Codecov Report

Merging #79 (b5484a6) into master (1d3e065) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #79      +/-   ##
==========================================
+ Coverage   57.12%   57.16%   +0.03%     
==========================================
  Files          27       27              
  Lines        2386     2388       +2     
==========================================
+ Hits         1363     1365       +2     
  Misses       1023     1023              

Impacted Files	Coverage Δ
src/Spaces/Chebyshev/Chebyshev.jl	54.34% <100.00%> (+0.67%)	⬆️

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