Saturnin style guide

I used to maintain a huge list of references to C++ Core Guideline, and to a lesser extent to Google C++ Style guide, but was cumbersome. Now that Saturnin is open sourced, it can benefit freely from tools like SonarCloud, and the SonarLint extension for Visual Studio 2022 which is way easier to use.

The style itself is enforced by a Clang Format file, which can be used through the Clang Power Tools extension for Visual Studio 2022.