ENUM type support

[wuputah]

No description provided.

[Reminiscent]

Hi, I'm very interested in this task. Could I work on it? Thank you very much! @wuputah @Tishj

[wuputah]

Thanks for your interest! I defer to @Tishj there on whether that makes sense and what the implementation plan should be. Most likely this should build on top of #56 / #97 where enums are copied from Postgres to the DuckDB catalog.

[Reminiscent]

@wuputah Thanks for your suggestion. I'll try to implement some types which are compatible now. I have some questions want to ask.

1. Are there any discuss about how to implement some types which are incompatible? And what is the principle.
2. Could you elaborate on the relationship between the catalog system implemented in this patch and the support for enum types? How does the catalog system specifically enable or facilitate the implementation of enum type support? Can you provide a concrete example of how the catalog changes in this patch would be utilized when implementing enum type support in pg_duckdb? Thanks!