Update clang-tidy to enforce naming style on global functions.

Is your feature request related to a problem? Please describe. After some consideration, I've decided our global functions should follow the lower_case naming convention as well.

Describe the solution you'd like

• Update the .clang-tidy file to enfore lower_case naming style for global / static functions.
• Run a clang-debug build (x64-linux-clang-debug), (arm64-osx-clang-debug), etc... and verify it compiles and clang-tidy job passes.

Describe alternatives you've considered I considered keeping the global functions CamelCase but I want to adhere to CppCoreGuidelines as much as possible. CamelCase will be reserved for types.

Additional context