Implement getUDTs method

[Algebrazebra]

I ran into the fact that the getUDTs method isn't implemented when writing a Slick extension for DuckDB.

This implementation uses a query against duckdb_types() and maps the DuckDB result columns to the column names required by the JDBC interface definition:

• database_name -> TYPE_CAT
• schema_name -> TYPE_SCHEM
• type_name -> TYPE_NAME
• comment -> REMARKS
• CLASS_NAME returned as NULL

The types themselves are mapped to the base type when a scalar base type is available, but STRUCT and UNION don't have one so it maps to NULL.

[Algebrazebra]

Ah I know what the problem is, I had x_index as myint before but renamed it to have the exact same examples as in the docs. Which changes the matches of the %m typeNamePattern. Then I ran the tests on the previous build artifact before creating the PR. I'll double-check locally, sorry for the noise/wasted runs.

[Algebrazebra]

My changes were back-ported by @staticlibs and made it into the v1.5.20 release.

This is why I am closing this PR.

[staticlibs]

@Algebrazebra

Sorry for the confusion, this PR is still useful for the main branch. Just I am waiting with merging it (and a few other PRs too) to have the updated engine sources to be integrated into main first. And the main branch in duckdb/duckdb CI has not run for some time. So I will open this to be integrated later when the main is updated.