Add neq dyn scalar kernel

[matthewmturner]

Which issue does this PR close?

Closes #1113 task neq_dyn_scalar

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[codecov-commenter]

Codecov Report

Merging #1118 (00a622f) into master (37b843b) will increase coverage by 0.00%.
The diff coverage is 85.18%.

@@           Coverage Diff           @@
##           master    #1118   +/-   ##
=======================================
  Coverage   82.33%   82.33%           
=======================================
  Files         169      169           
  Lines       49773    49800   +27     
=======================================
+ Hits        40981    41005   +24     
- Misses       8792     8795    +3     

Impacted Files	Coverage Δ
arrow/src/compute/kernels/comparison.rs	89.97% <85.18%> (-0.12%)	⬇️
arrow/src/datatypes/datatype.rs	66.38% <0.00%> (-0.43%)	⬇️
arrow/src/array/transform/mod.rs	85.43% <0.00%> (-0.14%)	⬇️
arrow/src/datatypes/field.rs	53.68% <0.00%> (+0.30%)	⬆️
parquet_derive/src/parquet_field.rs	66.21% <0.00%> (+0.45%)	⬆️

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