[USETUP]: Introduce SetupDeleteFile() and SetupMoveFile() (in addition to the already-existing SetupCopyFile()) in order to implement moving / renaming existing files. Will be used soon to make backups of system files, like the registry hive files just freshly created. - Make the SetupCopyFile() function closer to its win32 counterpart.
[USETUP]: Try to use correct flags for the NtCreateFile call that creates new file directories. DIRECTORY_ALL_ACCESS is not the correct flag, because it is used with the NtCreateDirectoryObject API that creates virtual "directories" in the NT object namespace; that's not our purpose here. This commit needs review to verify which flags are actually the best.