Add clang-tidy

This commit adds clang-tidy, and fixes most of the issues that tidy
finds that require manual intervention.  Note, it also reverts from
c++23 -> c++20 due to a bunch in clang-13 + libstdc++ + std::tuple
packs.  At such time as that's fixed, we can roll forward again.

Change-Id: I9bb5381866ef83dc75e41ef314377b19a79141f1
Signed-off-by: Ed Tanous <ed@tanous.net>
3 files changed