Removed unused files

[jorgecarleitao]

This PR removes leftovers from the migration.

[jorgecarleitao]

I am not sure we should use a issue for it, as I think we do not need a entry on the change log for this.

[codecov-commenter]

Codecov Report

Merging #22 (d912b29) into master (3d7cefb) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #22      +/-   ##
==========================================
+ Coverage   82.47%   82.49%   +0.01%     
==========================================
  Files         162      162              
  Lines       43414    43522     +108     
==========================================
+ Hits        35806    35902      +96     
- Misses       7608     7620      +12     

Impacted Files	Coverage Δ
arrow/src/array/transform/fixed_binary.rs	78.94% <0.00%> (-5.27%)	⬇️
arrow/src/array/transform/mod.rs	89.24% <0.00%> (-1.38%)	⬇️
arrow/src/compute/kernels/concat.rs	100.00% <0.00%> (ø)
arrow/src/array/transform/primitive.rs	100.00% <0.00%> (ø)
arrow/src/compute/kernels/aggregate.rs	73.40% <0.00%> (+0.07%)	⬆️
arrow/src/csv/writer.rs	83.01% <0.00%> (+0.27%)	⬆️
arrow/src/json/writer.rs	91.92% <0.00%> (+0.43%)	⬆️
arrow/src/array/data.rs	72.07% <0.00%> (+0.90%)	⬆️

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