Factor out constraints into separate methods

Factor out constraints into separate methods

Fixed issue where PostgreSQL dialect options such as ``postgresql_include``
on :class:`.PrimaryKeyConstraint` and :class:`.UniqueConstraint` were
rendered in the wrong position when combined with constraint deferrability
options like ``deferrable=True``. Pull request courtesy G Allajmi.

Fixes: #12867
Closes: #13003
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/13003
Pull-request-sha: 1a9216062f12cba2695b0b4a1407e092556c2305

Change-Id: I8c55d8faae25d56ff63c9126d569c01d8ee6c7dd
(cherry picked from commit 9fe3c3cd30bd7d4afc877bb2243ba7679ebe185d)