Use new DecimalArray creation API in parquet crate

[alamb]

Builds on #1223 so draft until that is done

Rationale:

#1223 introduces a more performant and idiomatic API for creating DecimalArrays than DecimalBuilder so update the code to use that.

[codecov-commenter]

Codecov Report

Merging #1247 (f204604) into master (aac1844) will increase coverage by 0.02%.
The diff coverage is 91.82%.

@@            Coverage Diff             @@
##           master    #1247      +/-   ##
==========================================
+ Coverage   82.96%   82.98%   +0.02%     
==========================================
  Files         178      178              
  Lines       51547    51659     +112     
==========================================
+ Hits        42765    42870     +105     
- Misses       8782     8789       +7     

Impacted Files	Coverage Δ
arrow/src/array/mod.rs	100.00% <ø> (ø)
arrow/src/datatypes/datatype.rs	66.40% <66.66%> (-0.41%)	⬇️
parquet/src/arrow/array_reader.rs	78.31% <85.71%> (+0.10%)	⬆️
arrow/src/array/array_binary.rs	93.39% <93.16%> (-0.10%)	⬇️
arrow/src/array/builder.rs	86.73% <100.00%> (-0.04%)	⬇️
arrow/src/array/data.rs	83.13% <100.00%> (+0.10%)	⬆️
arrow/src/compute/kernels/cast.rs	95.21% <100.00%> (+<0.01%)	⬆️
arrow/src/csv/reader.rs	88.12% <100.00%> (ø)
parquet/src/arrow/arrow_writer.rs	97.96% <100.00%> (-0.02%)	⬇️
parquet/src/arrow/converter.rs	63.96% <100.00%> (-0.39%)	⬇️
... and 5 more

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[alamb]

FYI @liukun4515

[liukun4515]

LGTM