refactor: rename drop_db / drop_database to drop_all_tables, expose database from connection (#2098)

If we start supporting external catalogs then "drop database" may be
misleading (and not possible). We should be more clear that this is a
utility method to drop all tables. This is also a nice chance for some
consistency cleanup as it was `drop_db` in rust, `drop_database` in
python, and non-existent in typescript.

This PR also adds a public accessor to get the database trait from a
connection.

BREAKING CHANGE: the `drop_database` / `drop_db` methods are now
deprecated.

nodejs/src/connection.rs

@@ -187,4 +187,9 @@ impl Connection {
     pub async fn drop_table(&self, name: String) -> napi::Result<()> {
         self.get_inner()?.drop_table(&name).await.default_error()
     }
+
+    #[napi(catch_unwind)]
+    pub async fn drop_all_tables(&self) -> napi::Result<()> {
+        self.get_inner()?.drop_all_tables().await.default_error()
+    }
 }