Implement xxhash algorithms as part of the expression API

### Is your feature request related to a problem or challenge?

I am currently in need of using datafusion SQL query engine (through delta-rs merge operation) to hash with a specific hashing algorithm.

https://xxhash.com/
https://github.com/Cyan4973/xxHash
Rust implementation : https://crates.io/crates/twox-hash

### Describe the solution you'd like

I'd like the hashing functions xxhash32 and xxhash64 to be part of [datafusion expression API](https://datafusion.apache.org/user-guide/expressions.html) so the functions can be used in SQL context for hashing data.

Start with the linked DataFusion expression API documentation and the twox-hash crate to understand the requested xxhash32 and xxhash64 functions. Identify the relevant expression and SQL integration tests; the work is done when both functions can be called from SQL and their hash results are verified.

Written by the indexing model from the issue text.