Support for Variant/Dynamic/JSON types

[arnaudbriche]

Hi,

I'm just wondering if you are planning on supporting the new set of semi-structured data types.

[SpencerTorres]

This is how they are supported in clickhouse-go:

• Add Variant Type clickhouse-go#1453
• Add Dynamic Type clickhouse-go#1454
• Add JSON Type clickhouse-go#1455

I would like to add some support for them, but we would need to make sure it fits the performance goals of ch-go. There's some overhead for working with these types, and we need to find a user-friendly way to read/write this type of data.