Modularization of copy_msvc_libraries cmake funct

Created a new folder in Citra's root called CMakeModules that should
contain cmake functions used by the various CMakeLists.txt.

CMakeLists.txt

@@ -1,5 +1,6 @@
 # CMake 3.2 required for cmake to know the right flags for CXX standard on OSX
 cmake_minimum_required(VERSION 3.2)
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${PROJECT_SOURCE_DIR}/CMakeModules)
 
 function(download_bundled_external remote_path lib_name prefix_var)
     set(prefix "${CMAKE_BINARY_DIR}/externals/${lib_name}")