Filters USB devices to not be listed in disk selection dialog. Add a config value to allow USB devices to show in selection dialog. Fixes installation on USB devices.

[happymab]

This PR fixes the installation on USB devices:

• USB devices are filtered out by default and not offered as installation devices
• A new config value allows optionally to disable the USB filter, show USB devices in the selection dialog and allow the installation
• A change in the mig module fixes the issue with failed installations on USB devices

[sysrich]

Looks good to me but also includes the changes from your other PR

It's good practice to use different branches for each topic so I'm not forced to merge everything all together

I will in this case.. but it will have to wait a few more days so have the time to test it more thoroughly as it's a bigger set of changes now :)

Thanks for the contributions !

[happymab]

Right, I branched from the previous branch instead of main. I will keep that in mind next time.