3.2 Move non-PDO DB extensions to PECL
Issue: PHP 5.1 introduces PDO, an extension that unifies Database APIs. With this we do not "need" older extensions to access databases anymore.
Discussion: We can not remove the "old" extensions, as at least OCI8 and MySQLi provide a very rich set of features, which are not all supported by PDO. Some "old" extensions can probably be moved to PECL as they are either unmaintained, or superseded by PDO.