Add gt dyn scalar kernel

[matthewmturner]

Which issue does this PR close?

Closes #1113 task gt_dyn_scalar

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[codecov-commenter]

Codecov Report

Merging #1116 (75a1ae0) into master (0d825c1) will increase coverage by 0.00%.
The diff coverage is 85.18%.

@@           Coverage Diff           @@
##           master    #1116   +/-   ##
=======================================
  Coverage   82.32%   82.32%           
=======================================
  Files         168      168           
  Lines       49577    49658   +81     
=======================================
+ Hits        40812    40879   +67     
- Misses       8765     8779   +14     

Impacted Files	Coverage Δ
arrow/src/compute/kernels/comparison.rs	90.41% <85.18%> (-0.47%)	⬇️
arrow/src/datatypes/field.rs	53.37% <0.00%> (-0.31%)	⬇️
parquet_derive/src/parquet_field.rs	66.21% <0.00%> (-0.23%)	⬇️
arrow/src/array/transform/mod.rs	85.43% <0.00%> (-0.14%)	⬇️
arrow/src/datatypes/datatype.rs	66.80% <0.00%> (+0.42%)	⬆️

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[alamb]

I love how simple these PRs are both to review as well as their implementation 👨‍🍳 very nice