Enforce formatting

[myurkin]

We have description of the code style - https://github.com/adda-team/adda/wiki/CodeStyleGuide. But it is neither comprehensive (covers all cases) nor enforced. It would be great to implement testing for the style in Github Actions - probably some existing standard can be adopted for that. And, naturally, it should be as much close to the existing de-facto style as possible.

The first step is to study existing standards for C code, and whether they are readily available in IDEs and automatic tools.

[myurkin]

/cc @palatni

[Argencle]

To address the need for an enforceable and automated code style, I propose adopting clang-format as the primary tool for this purpose.

1. Widely Adopted: It's a well-established tool, supporting popular coding standards like LLVM and Google.
2. Customizable: We can create a .clang-format file tailored to closely match the existing de-facto ADDA style.
3. IDE Integration: It works seamlessly with major IDEs.
4. Automation-Friendly:
   • Can be integrated into GitHub Actions to check for code style adherence on pull requests.
   • Supports workflows like pre-commit hooks or git clang-format for local enforcement.

I believe this will simplify enforcement, improve consistency, and reduce manual efforts.