allow overriding Windows Wix main.wxs template

[jboss48]

I had the task of generating an MSI in French while also changing the installation scope from per-machine to per-user. The default GluonFX/Substrate plugin hardcodes the MSI template (main.wxs) and the installation scope, making the task non-trivial.

Challenge
The plugin seems to copy main.wxs from its internal resources and immediately invokes WiX to build the MSI.

Solution
Forked the project to introduce configurable system properties, something like:

        var mainWxsOverride=System.getProperty("gluonfx.wix.main");
        if (mainWxsOverride!=null) {
            Path custom = Paths.get(mainWxsOverride);
            if(Files.exists(custom))
                Files.copy(custom, wixPath, REPLACE_EXISTING);
            // TODO else
        } else {
            FileOps.copyResource("/native/windows/wix/main.wxs", wixPath);
        }
  ....
        String cultureOverride=System.getProperty("gluonfx.wix.culture");
        String culture="en-us";
        if(cultureOverride!=null)
            culture=cultureOverride;
        processArgs.addAll(List.of(
                WixTool.LIGHT.getPath(),
                "-nologo",
                "-spdb",
                "-sw1076", // https://github.com/wixtoolset/issues/issues/5938
                "-ext", "WixUtilExtension",
                "-ext", "WixUIExtension",
                "-cultures:"+culture,
                "-out", msiPath.toString(),
                wixObjPath.toString()
        ));

Outcome

• Successfully generated a French MSI with per-user installation.

• This approach can be reused for other languages or custom MSI templates in future projects.

Conclusion
I am open to any alternative solutions or suggestions if there is a better way to handle this in the plugin or WiX configuration that I might have missed. My goal was to implement a clean, maintainable solution without relying on hacks, but I welcome feedback if there is a more efficient or standard approach.