Support usb mounting

[Nothing4You]

This could be used as an alternative to kickstart CentOS installation as RHEL 8 removed floppy support.

This should be analogous to floppy_files, floppy_dirs and floppy_img_path as far as I understand.

[Nothing4You]

If this is implemented it would also be useful to be able to label the drive, e.g. OEMDRV allows redhat-based systems to automatically start the kickstart installation

[Nothing4You]

related:

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/considerations_in_adopting_rhel_8/hardware-enablement_considerations-in-adopting-rhel-8#removed-device-drivers_hardware-enablement
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/performing_an_advanced_rhel_installation/index#making-a-kickstart-file-available-on-a-local-volume_making-kickstart-files-available-to-the-installation-program

https://www.zdnet.com/article/linus-torvalds-prepares-to-wave-goodbye-to-linux-floppy-drives/