support parameterized query in Postgres extended query protocol

[BugenZhao]

We have the basic support for Postgres extended query protocol. However, as there is no SLT syntax available for the individual steps of Parse and Bind, we always query with a full SQL and no parameters.

sqllogictest-rs/sqllogictest-engines/src/postgres/extended.rs

Lines 191 to 195 in 58673cb

	let stmt = self.client.prepare(sql).await?;
	let rows = self
	.client
	.query_raw(&stmt, std::iter::empty::<&(dyn ToSql + Sync)>())
	.await?;