Fix/csv file class

[eddiesshop]

How to test

Get your most problematic CSV file, and see if this class will read it and process the rows.

$ wp shell
> $csv = ( new FileImportFactory )->get_file( '/path/to/file' )->getIterator();
> foreach ($csv as $row ) {
>     var_dump( $row );
> }

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I think this is the best way to handle charsets, but would appreciate if someone more knowledgeable than me could check or confirm.

• [x] confirmed that PHPCS has been run

[eddiesshop]

Thanks for the review @naxoc!

That makes sense, I'll create another PR adding that flexibility.