[TASK] Delete records not in a site language

[schliesser]

This check deletes all records that have a sys_language_uid not matching the configured languages in the corresponding site configuration.

Issue #119

[lolli42]

Hey.
Thank you!
At first, I'm not a huge fan of adding the site API as dependency to dbdoctor.
But I have to admit we should have a check like this, so there is probably no way around the dependency.
My current rough plan is like this: have a last 0.x release, then kickstart a 1.0 that has v12&v13 support only.
A check like this could go to a 1.1.
I would love to see if you continue to work on the change: We'll need proper coverage with tests that set up some sites. The core has examples on how this can be done relatively easily.