Add a way to move fields out of parquet Row

[SHaaD94]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
In our system, we read a lot of strings, stored in parquet. Until recently we've been using row.get_column_iter() and cloning all column values. It would be really nice if there would be a way move the ownership of column values out of the row.

Describe the solution you'd like
Move of internal fields structure out like this would work for us:

    pub fn into_columns(self) -> Vec<(String, Field)> {
        self.fields
    }

Describe alternatives you've considered
Currently, I just transmute the row into columns vector, but I don't really like keeping something as unsafe in my code base.

Additional context

[alamb]

label_issue.py automatically added labels {'parquet'} from #5842