Ensure common formatting of C++ code

[tomuben]

Background

Currently, there is no common formatting among the C++ code of the UDF client. We should use clang-format which could run as a commit githook.

Out of Scope

• old udfclient

Acceptance

1. Define a .clang-format file which specifies the formatting
2. Run clang-format and fix formatting
3. Add a nox task which checks formatting
4. Add nox task to Github workflow for CI checks.