[Rust][DataFusion] Benchmark and potentially optimize the to_timestamp function

[asfimport]

As suggested by @jhorstmann on #8142 (comment)

I'd be interested in a benchmark of the to_string function or the kernel, maybe one for the happy case with T and Z and one for the last fallback. From my experience with Java, parsing timestamps can be rather slow and it might be worth writing a specialized implementation.

Reporter: Andrew Lamb / @alamb

_{Note: This issue was originally created as ARROW-9955. Please see the migration documentation for further details.}

[thisisnic]

Closing this issue as Rust development has moved to apache/arrow-rs and Datafusion to apache/datafusion.

If this is still relevant, feel free to open a new issue in one of those repos. Thanks!