We want to host pg_duckdb (starting with v0.3.1) on Neon.
This PR replaces https://github.com/neondatabase/neon/pull/10350 which
was for older pg_duckdb v0.2.0
Use cases
- faster OLAP queries
- access to datelake files (e.g. parquet) on S3 buckets from Neon
PostgreSQL
Because neon does not provide superuser role to neon customers we need
to grant some additional permissions to neon_superuser:
Note: some grants that we require are already granted to `PUBLIC` in new
release of pg_duckdb
[here](3789e4c509/sql/pg_duckdb--0.2.0--0.3.0.sql (L1054))
```sql
GRANT ALL ON FUNCTION duckdb.install_extension(TEXT) TO neon_superuser;
GRANT ALL ON TABLE duckdb.extensions TO neon_superuser;
GRANT ALL ON SEQUENCE duckdb.extensions_table_seq TO neon_superuser;
```