Support for lquery (#1710)

* initial lquery version

* share code between ltree/lquery

* more lquery functions

* fix rebase issues

* add version comment

* Update sqlx-core/src/postgres/types/lquery.rs

Co-authored-by: Austin Bonander <austin.bonander@gmail.com>

Co-authored-by: Bastian Schubert <bastian.schubert@crosscard.com>
Co-authored-by: Austin Bonander <austin.bonander@gmail.com>

sqlx-macros/src/database/postgres.rs

@@ -20,6 +20,8 @@ impl_database_ext! {
 
         sqlx::postgres::types::PgLTree,
 
+        sqlx::postgres::types::PgLQuery,
+
         #[cfg(feature = "uuid")]
         sqlx::types::Uuid,