Add tidy check for const and ref members

[godexsoft]

Summary

We should enforce https://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines/avoid-const-or-ref-data-members.html#cppcoreguidelines-avoid-const-or-ref-data-members

I tried to add this check locally and it yields a lot of warnings.

Motivation

Using const and reference members is bad practice.

Solution

Add a clang-tidy check and fix all errors manually.