Feature: Add the `NULLABLE` field to `information_schema.columns`

[hantmac]

Summary

Description for this feature.

I am developing a custom driver for metabase which is a powerful BI tool. The metabase.driver SDK collect column metadata from table information_schema.columns and it will read the nullable field but the databend only has is_nullable field which is varchar type. SO databend should add the nullable field to table information_schema.columns which is TinyInt type.
1 means is_nullable = YES.

[BohuTANG]

cc @TCeason