[Enhancement] Improve user experience in installation process under Windows

[Andreas0602]

Description

When attempting to install mucommander-1.5.0.msi (nightly build) while an older version is already installed, the following error message will appear:

This is not user-friendly. The installer should offer to automatically uninstall the old version.

Under macOS, this issue does not exist.

[ahadas]

@Andreas0602 on which version of Windows? on Windows 10 I get a message saying that the folder exists (see below) and if I choose to continue, the existing version is overridden

[Andreas0602]

@ahadas, Windows 10 Professional.