Improve DuckDB presence within IntelliJ IDEA

[rsmckinney]

As the screen capture shows, DuckDB is available as a data source within IntelliJ IDEA. However, DuckDB is in the basic support category, as opposed to the "complete support" category.

This is a real disappointment when using DuckDB in IntelliJ in terms of SQL rendering, code completion, etc.

Even with the dialect set to PostgreSQL, queries that use extensions fail to parse in the editor. Usage of all those awesome extensions render in red and fail code completion.

Would be nice to work with JetBrains to level up here, it would help DuckDB gain traction with Java.