Common/CommonFuncs: Remove now-unneccessary ArraySize function

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.

Source/Core/Common/CommonFuncs.h

@@ -4,17 +4,9 @@
 
 #pragma once
 
-#include <cstddef>
 #include <string>
 #include "Common/CommonTypes.h"
 
-// Will fail to compile on a non-array:
-template <typename T, size_t N>
-constexpr size_t ArraySize(T (&arr)[N])
-{
-  return N;
-}
-
 #ifndef _WIN32
 
 // go to debugger mode