cmake: move find-modules to root cmake dir

externals/cmake-modules/WindowsCopyFiles.cmake

@@ -1,27 +0,0 @@
-# SPDX-FileCopyrightText: 2018 yuzu Emulator Project
-# SPDX-License-Identifier: GPL-2.0-or-later
-
-# This file provides the function windows_copy_files.
-# This is only valid on Windows.
-
-# Include guard
-if(__windows_copy_files)
-	return()
-endif()
-set(__windows_copy_files YES)
-
-# Any number of files to copy from SOURCE_DIR to DEST_DIR can be specified after DEST_DIR.
-# This copying happens post-build.
-function(windows_copy_files TARGET SOURCE_DIR DEST_DIR)
-    # windows commandline expects the / to be \ so switch them
-    string(REPLACE "/" "\\\\" SOURCE_DIR ${SOURCE_DIR})
-    string(REPLACE "/" "\\\\" DEST_DIR ${DEST_DIR})
-
-    # /NJH /NJS /NDL /NFL /NC /NS /NP - Silence any output
-    # cmake adds an extra check for command success which doesn't work too well with robocopy
-    # so trick it into thinking the command was successful with the || cmd /c "exit /b 0"
-    add_custom_command(TARGET ${TARGET} POST_BUILD
-        COMMAND ${CMAKE_COMMAND} -E make_directory ${DEST_DIR}
-        COMMAND robocopy ${SOURCE_DIR} ${DEST_DIR} ${ARGN} /NJH /NJS /NDL /NFL /NC /NS /NP || cmd /c "exit /b 0"
-    )
-endfunction()