Windows MSI installer, convert from WIX v3 to v4

About a year ago, Wix 4 was released (
https://www.firegiant.com/blog/2023/4/5/wix-v4-and-heatwave-v1-released/ ).
In Feb 2025, support for Wix 3 will be over.
So we need to convert from version 3 to version 4.

Several things to be done are described in https://wixtoolset.org/docs/fourthree,

Things to note:

• instead of "candle.exe", or "light.exe" , the traditional Wix compiler and linker, there is only one tool, wix.exe
• The XML schema has changed - the namespace, several elements (e.g attribute Win64="yes" to Bitness="always64" or something like that.
• MySQL has done it recently, it makes sense to study what they did in https://github.com/mysql/mysql-server/commit/1d729a9e5c5496d072b1bfc9c56f18dbd8711b5d