Add Float16/Half-float logical type to Parquet

[anjakefala]

Hi!

I wanted to let you know that there is a proposal for an addition of Logical Float-16 (with Fixed Length Byte Array physical typed) to the Parquet Format: apache/parquet-format#184.

The vote has passed. Close to completion are a apache/parquet-java#1142, apache/arrow#36073, and a apache/arrow#37599. AFAICT, there is no implementation that has been begun in arrow-rs. I opened an issue there too.

Float-16 is supported in #1050, and it would be great to expand that support to Rust Parquet.