Ask player to configure default install path during setup on Windows

[awantoch]

Tangentially related to #737

Currently, the default install path is only in the Settings.

However, since Windows users often have multiple drives, and change their install paths, the installer/setup process should also ask the player up front where to install games.

Since other OS' don't have this need as frequently (i.e., macOS users rarely have different drives/partitions), this is only needed for the Windows installer.