[11.x] Add Databases nightly workflow

[Jubeki]

Alternative to https://github.com/laravel/framework/pull/51193

This PR adds a database nightly workflow, which runs preview versions of databases (currently only MariaDB) to make sure upcoming versions are supported.

Note: The line were it runs on pull_requests needs to be removed before merge. It is there only too make sure the tests pass here.

[github-actions[bot]]

Thanks for submitting a PR!

Note that draft PR's are not reviewed. If you would like a review, please mark your pull request as ready for review in the GitHub user interface.

Pull requests that are abandoned in draft may be closed due to inactivity.

[driesvints]

Thanks @Jubeki!