Otherwise we include Windows headers in the entire codebase through CommonFuncs.h

Gets these functions out of the global namespace.

SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.

This unifies GetModuleFileName calls between Dolphin and WinUpdater
and allows to gracefully remove MAX_PATH limit from GetExePath

Since C++17, non-member std::size() is present in the standard library
which also operates on regular C arrays. Given that, we can just replace
usages of ArraySize with that where applicable.

In many cases, we can just change the actual C array ArraySize() was
called on into a std::array and just use its .size() member function
instead.

In some other cases, we can collapse the loops they were used in, into a
ranged-for loop, eliminating the need for en explicit bounds query.