Simplified code

[jorgecarleitao]

This PR removes duplicated code to create a MutableBinaryArray and MutableUtf8Array. The code has its fair share of unsafe, so we minimize risks with less.

[codecov]

Codecov Report

Merging #760 (544d692) into main (cc65b0e) will decrease coverage by 0.06%.
The diff coverage is 98.03%.

@@            Coverage Diff             @@
##             main     #760      +/-   ##
==========================================
- Coverage   70.97%   70.91%   -0.07%     
==========================================
  Files         313      314       +1     
  Lines       16923    16839      -84     
==========================================
- Hits        12011    11941      -70     
+ Misses       4912     4898      -14     

Impacted Files	Coverage Δ
src/array/binary/mutable.rs	77.27% <ø> (-3.30%)	⬇️
src/array/mod.rs	69.29% <ø> (ø)
src/array/physical_binary.rs	97.87% <97.87%> (ø)
src/array/utf8/mutable.rs	80.47% <100.00%> (-5.36%)	⬇️
src/compute/arithmetics/time.rs	25.68% <0.00%> (-0.92%)	⬇️
src/io/avro/read/schema.rs	55.91% <0.00%> (+1.07%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cc65b0e...544d692. Read the comment docs.