Refactor ftable scan as a function

[andyfengHKU]

This PR removes FactorizedTableScan operator and instead make it a scan function executed by InQueryCall operator.

Additionally this PR moves several functions from its header file to corresponding cpp file.

[codecov]

Codecov Report

Attention: 6 lines in your changes are missing coverage. Please review.

Comparison is base (fb860a6) 93.45% compared to head (4d0d68d) 93.49%.
Report is 9 commits behind head on master.

Files	Patch %	Lines
...ator/persistent/reader/csv/parallel_csv_reader.cpp	84.21%	3 Missing ⚠️
src/processor/operator/call/in_query_call.cpp	96.42%	1 Missing ⚠️
...erator/persistent/reader/csv/serial_csv_reader.cpp	97.29%	1 Missing ⚠️
...essor/operator/table_scan/ftable_scan_function.cpp	95.65%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2921      +/-   ##
==========================================
+ Coverage   93.45%   93.49%   +0.03%     
==========================================
  Files        1117     1115       -2     
  Lines       42687    42694       +7     
==========================================
+ Hits        39895    39918      +23     
+ Misses       2792     2776      -16     

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