Refactored JSON read to split IO-bounded from CPU-bounded tasks

[jorgecarleitao]

This PR replaces the JSON reader by functions that offer the flexibility to read JSON asynchronously, via futures' AsyncBufRead or Tokios' AsyncBufReadExt.

The core idea of this PR, as it is for other parts of this crate, is that it separates functionality that is IO-bounded (read 1000 lines from a stream) from functionality that is CPU-bounded (parse 1000 strings into an arrow struct of 1000 rows).

The PR also refactors schema inference to make it easier to follow, use generics, etc.

[codecov]

Codecov Report

Merging #706 (2b0fe14) into main (39695e9) will decrease coverage by 0.11%.
The diff coverage is 76.78%.

@@            Coverage Diff             @@
##             main     #706      +/-   ##
==========================================
- Coverage   70.28%   70.17%   -0.12%     
==========================================
  Files         309      309              
  Lines       16873    16800      -73     
==========================================
- Hits        11860    11790      -70     
+ Misses       5013     5010       -3     

Impacted Files	Coverage Δ
src/io/json/mod.rs	100.00% <ø> (ø)
src/io/json/read/iterator.rs	63.15% <63.15%> (ø)
src/io/json/read/mod.rs	66.66% <66.66%> (ø)
src/io/json/read/deserialize.rs	68.42% <77.77%> (-5.27%)	⬇️
src/io/json/read/infer_schema.rs	80.48% <81.25%> (-0.71%)	⬇️
src/datatypes/schema.rs	32.00% <0.00%> (-12.00%)	⬇️
src/io/avro/read/schema.rs	53.68% <0.00%> (+1.05%)	⬆️

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