Add NORMALIZE to SQL String Functions while adding expanded Unicode Normalization support

[jqnatividad]

Description

Now that Polars has str.normalize with #20483.

Also, possibly add support for

text IS [NOT] [form] NORMALIZED → boolean (see PostgreSQL String Functions)

in SQL and str Polars library as the unicode-normalization crate has the required is_ functions.

https://docs.rs/unicode-normalization/latest/unicode_normalization/index.html#functions

[alexander-beedie]

Sounds like a plan; about to commit NORMALIZE(...) SQL support.

Can you split out the request for text IS [NOT] [form] NORMALIZED → boolean as a separate Issue? I took a quick look and it seems it will require an update to the upstream sqlparser-rs lib (which I can likely do, but we'll have to wait for the subsequent release of that lib to add support here). Easier to manage as separate Issues so I can close this one and keep the other on my radar👌