Summary:
Transactional DDL introduces support for interleaving DDL and DML statements within a transaction block.

This revision enables transactional ddl by default in release builds.

We had enabled transactional ddl by default in many tests. They will removed in a follow-up revision as some of those tests (regress) need to be duplicated for with and without txn ddl. #29148 will track this work.
Jira: DB-1839

Test Plan: Jenkins

Reviewers: bkolagani, myang, pjain, patnaik.balivada

Reviewed By: pjain

Subscribers: yql, ybase, rthallam, skumar, yyan

Differential Revision: https://phorge.dev.yugabyte.com/D45414