Use clang-tidy for static analysis

[tom91136]

Would be great if we can setup clang-tidy to perform checks in the CI. Note that clang-tidy is directly supported in CMake, we can simply do:

set(CMAKE_CXX_CLANG_TIDY
  clang-tidy;
  -format-style='my-style;
 ...
)

The warning shows up in the build step:

[ 33%] Building CXX object CMakeFiles/test.dir/main.cpp.o
/home/tom/test/main.cpp:3:1: warning: do not use namespace using-directives; use using-declarations instead [google-build-using-namespace]
using namespace std;

If configured correctly, the output should be identical to CLion's diagnostics.

Once this is done we can open a PR to squash all warnings. This would probably need to be behind a flag (e.g SIMENG_CLANG_TIDY) because not everyone has clang-tidy.