Begin migration from sys/win32 to sys/windows

core/sys/windows/userenv.odin

@@ -0,0 +1,10 @@
+package sys_windows
+
+foreign import userenv "system:Userenv.lib"
+
+@(default_calling_convention="stdcall")
+foreign userenv {
+	GetUserProfileDirectoryW :: proc(hToken: HANDLE,
+	                                 lpProfileDir: LPWSTR,
+	                                 lpcchSize: ^DWORD) -> BOOL ---
+}