CI: Run clang-tidy, clang-format, cppcheck

[Neverlord]

This was originally a task in #212. Basically, we want to add additional quality gates to our CI:

• clang-format to make sure we use a consistent coding style
• clang-tidy for making sure the code avoids common pitfalls (bugprone checks) and follows some best practices for readability
• cppcheck to have an additional static analyzer look over the source code (Zeek's Coverity runs also cover Broker)