Repository as a reusable module

Looking at the turbulence TC, they have a group with multiple (currently two) repositories. The turbulence-community repository is actually:

included with OpenFOAM® plugins as a collection of nested submodules.

This repository is actually itself a collection of Git modules, most of which are hosted on GitHub.

We could also start making such repositories ourselves and aim for something more reusable (for example, the clang-format cofig). I would then ask to have a similar group and repository for us here.