[11.x] Add MariaDB driver

[staudenmeir]

The more MariaDB diverges from MySQL, the more tedious and hacky it gets to support both DBMS with a single driver.
Now that Laravel 11 provides a dedicated database config for MariaDB (#48455), it makes sense to also have a dedicated driver.

Upgrade Guide

The PR is not a breaking change and you can still use MariaDB with the MySQL driver. The ultimate goal, of course, is to remove all MariaDB-specific code from MySQL classes (grammars etc.), but I would only do that in Laravel 12. This gives MariaDB users a year to adjust their config and test the driver. They should switch to the new driver to benefit from MariaDB-specific features, but it doesn't break their application if they miss this change. Ideally, @laravel-shift can recommend it.

TODO

• The integration tests require a workaround to run on MariaDB until we also adjust the Testbench config.
• When [11.x] Improve MySQL connect init time by setting all our variables in a single shot #50044 gets merged into the master branch, the MariaDbConnector class needs to be adjusted.
• [10.x] Add Lateral Join to Query Builder #50050 also benefits from this PR since MariaDB doesn't support lateral joins and we can throw a clean exception.

Plans

#48888 has already collected MariaDB-specific features/improvements we can implement. There are also a few older tickets about differences between MySQL and MariaDB we can revisit.

[taylorotwell]

Thanks 👍

[GrahamCampbell]

FYI, I'll re-target my PR and include the changes both for MySQL and MariaDB.