Refactoring ignore_columns from list to set

[mahedeeb]

Across all the modules, the considered features are updated after taking into account the ignore_columns as follows:

if ignore_columns is not None:
    string_columns = [col_i for col_i in string_columns if col_i not in ignore_columns]

It is a best practice to change the ignore_columns from a list type to set type to speed up the code.