Allow org-wide configuration

[boesing]

Feature Request

Q	A
New Feature	yes
BC Break	no

Summary

It might be handy to have org-wide configuration available for CI stuff. Renovate for examples allows config merging with organization config:

https://github.com/laminas/.github/blob/main/renovate-config.json
https://github.com/laminas/laminas-servicemanager/blob/c97780e74ac5c2fdf2aa4876bccdc718b6fc6ed9/renovate.json#L4

The idea of this feature request is to allow .laminas-ci.json files being available in the .github repository as well.
Once it is available, its being merged.
It should not be dependend on a config entry (as most projects do not even have .laminas-ci.json in-place.
So I'd always check the organization for having a .laminas-ci.json and if so, that is used as a default and then merges explicit configuration with the project file (if available).