Improve MSI

[kenkendk]

The current MSI UI is non-existing and this makes it impossible to toggle various features.
There is some support in wixl that supports UIs, so hopefully there is enough to get at least on-par:
https://gitlab.gnome.org/GNOME/msitools/-/merge_requests/30

[ts678]

Maybe not impossible, as I did it the ugly way. I'm not looking at the merge request closely, but I notice it's not merged.
If this issue can't be closed, possibly a manual workaround can be documented for dealing with the start at login feature.

I am not a lawyer, and I don't know the risk level from not showing a click-through license. Mainly worried about liability.
MIT license is linked from the About page of the GUI, but is that enough? I can't immediately find it in CommandLine.exe
licenses\license.txt exists, but doesn't show the copyright holder.

[kenkendk]

I managed to get a working WixUI_FeatureTree UI sequence up with wixl so now we are on-par with the previous installers. It is also in a state that we can work new feature in as needed later.