Write the clang-tidy file OpenBMC needs

Now that CI can handle clang-tidy, and a lot of the individual fixes
have landed for the various static analysis checks, lets see how close
we are.

This includes bringing a bunch of the code up to par with the checks
that require.  Most of them fall into the category of extraneous else
statements, const correctness problems, or extra copies.

Tested:
CI only.  Unit tests pass.

Signed-off-by: Ed Tanous <ed@tanous.net>
Change-Id: I9fbd346560a75fdd3901fa40c57932486275e912
diff --git a/include/webassets.hpp b/include/webassets.hpp
index 9944dfd..c2a6851 100644
--- a/include/webassets.hpp
+++ b/include/webassets.hpp
@@ -65,7 +65,7 @@
 
     for (const std::filesystem::directory_entry& dir : paths)
     {
-        std::filesystem::path absolutePath = dir.path();
+        const std::filesystem::path& absolutePath = dir.path();
         std::filesystem::path relativePath{
             absolutePath.string().substr(rootpath.string().size() - 1)};
         if (std::filesystem::is_directory(dir))