Build Windows installer using cargo-wix

[martinling]

Builds a Windows MSI installer using cargo-wix, that installs the Packetry application along with all the DLL files required for GTK4 and its dependencies.

[martinling]

There's a few things this doesn't do yet, which we might want it to:

• Sign the installer so that it runs without warnings.
• Add the application to the Start menu and/or desktop.
• Associate an icon with the application (see also Proposal for app icon #95).
• Associate .pcap files with the application.
• Display the license during installation.
• Install a copy of the license with the application.

It works though, and could be merged as-is and improved later.