replace cast string to fixed function in driver.cpp

[AEsir777]

ToDo

• add more tests
• fixed float conversion bug (probably just because the digits are full)
• error message

	new	old
FLOAT(20) x 100000	5194.5	7127.13200

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (5ce92b8) 89.57% compared to head (731a42c) 89.56%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2221      +/-   ##
==========================================
- Coverage   89.57%   89.56%   -0.02%     
==========================================
  Files        1006     1006              
  Lines       36273    36313      +40     
==========================================
+ Hits        32493    32523      +30     
- Misses       3780     3790      +10     

Files	Coverage Δ
...rocessor/operator/persistent/reader/csv/driver.cpp	97.72% <100.00%> (+0.59%)	⬆️

... and 4 files with indirect coverage changes

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[acquamarin]

The casting for numeric types are very similar: You can implement the casting for numeric types in the template function body, and use specialization for other types. So you don't need to duplicate the code for numeric type casting.
The numeric type casting:

 if (strVal.empty() || isNull(strVal)) {
        vector->setNull(rowToAdd, true /* isNull */);
        return;
    } else {
        vector->setNull(rowToAdd, false /* isNull */);
    }

    function::simpleIntegerCast<T>(
        strVal.data(), strVal.length(), value, vector->getDataType());
    vector->setValue(rowToAdd, value);

Using this generic templated numeric type casting function, you don't need to duplicate the common code for all numeric types.
Anyways, feel free to ping me if you have questions regarding to the refactor. Or you can leave it to me.