Set codepage for winapi to utf-8 in the manifest file

This actually works on windows 10 1903 and later though

packaging/windows/SConscript

@@ -13,6 +13,8 @@ for bin in binaries:
         res = []
     env[bin + "_res"] = res
 
+Depends(env["wesnoth_res"], File("wesnoth.exe.manifest"))
+
 def WindowsInstaller(env, files):
     files = [Entry(file) for file in Flatten(files)]
     env["NSIS_INSTALL_FILES"] = ""

packaging/windows/wesnoth.exe.manifest

@@ -25,6 +25,7 @@
     <asmv3:windowsSettings>
       <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">true</dpiAware>
       <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">PerMonitorV2</dpiAwareness>
+      <activeCodePage xmlns="http://schemas.microsoft.com/SMI/2019/WindowsSettings">UTF-8</activeCodePage>
     </asmv3:windowsSettings>
   </asmv3:application>
 </assembly>