MSI link to iceservice installer

[pepone]

For a separare PR:

It would be helpful to include text + link to https://docs.zeroc.com/ice/latest/cpp/using-the-ice-service-installer.

Originally posted by @bernardnormier in #4447 (comment)

[pepone]

The WIXUI_EXITDIALOGOPTIONALTEXT is plain text cannot contain links, we can create a custom exitdialog base on the default exit dialog and add an Hyperlink control.