format: expose indexes in catalog metadata

### What feature or improvement would you like to see?

- [JDBC: DatabaseMetaData.getIndexInfo](https://docs.oracle.com/en/java/javase/17/docs/api/java.sql/java/sql/DatabaseMetaData.html#getIndexInfo(java.lang.String,java.lang.String,java.lang.String,boolean,boolean))
- [ODBC: SQLStatistics](https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqlstatistics-function)
- BigQuery: https://github.com/adbc-drivers/bigquery/issues/118 (point 17)
- PostgreSQL: https://github.com/apache/arrow-adbc/issues/3971 (point 6)

We may have to figure out how to accommodate database-specific columns.