add basic wix template

tools/rust/cargo-proton-bundle/src/bundle/templates/main.wxs

@@ -0,0 +1,13 @@
+<?if $(sys.BUILDARCH)="x86"?>
+    <?define Win64 = "no" ?>
+    <?define PlatformProgramFilesFolder = "ProgramFilesFolder" ?>
+<?elseif $(sys.BUILDARCH)="x64"?>
+    <?define Win64 = "yes" ?>
+    <?define PlatformProgramFilesFolder = "ProgramFiles64Folder" ?>
+<?else?>
+    <?error Unsupported value of sys.BUILDARCH=$(sys.BUILDARCH)?>
+<?endif?>
+
+<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
+    
+</Wix>