feat: High-level API to get rows and column values from in-memory queue

[laysakura]

Fixes: #118

[codecov]

Codecov Report

Merging #119 (ed5c55f) into main (5ae6009) will increase coverage by 0.19%.
The diff coverage is 93.57%.

@@            Coverage Diff             @@
##             main     #119      +/-   ##
==========================================
+ Coverage   86.86%   87.06%   +0.19%     
==========================================
  Files         200      201       +1     
  Lines       11593    11847     +254     
==========================================
+ Hits        10070    10314     +244     
- Misses       1523     1533      +10     

Impacted Files	Coverage Δ
springql-core/src/api/error.rs	0.00% <ø> (ø)
springql-core/src/api/low_level_rs.rs	94.33% <ø> (ø)
springql-core/src/expression.rs	75.44% <0.00%> (+1.19%)	⬆️
springql-core/src/stream_engine.rs	95.00% <ø> (ø)
...ngql-core/src/stream_engine/autonomous_executor.rs	93.90% <0.00%> (-1.16%)	⬇️
...e/autonomous_executor/row/value/sql_convertible.rs	0.00% <0.00%> (ø)
.../src/stream_engine/time/duration/event_duration.rs	25.00% <0.00%> (ø)
...ration/wall_clock_duration/wall_clock_stopwatch.rs	90.90% <ø> (ø)
...ne/autonomous_executor/row/foreign_row/sink_row.rs	88.88% <40.00%> (-6.35%)	⬇️
...e/src/sql_processor/sql_parser/pest_parser_impl.rs	87.62% <50.00%> (-0.29%)	⬇️
... and 27 more

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