All drivers and `nut-scanner` should use `nut_usb_get_string` instead of libusb's `*_simple` and `*_ascii`

[jimklimov]

• Device discovery, where still custom
• String data point queries
• Copy of the method (or separate .c/.h file to share) for nut-scanner? => Currently solved as a copy, more methods were needed and method pointers were involved => Port and use a variant of nut_usb_get_string() for nut-scanner #2626

Originally posted in #2604 (comment)

[tormodvolden]

Just note that some drivers sometimes, like the hunnox protocol when "unlocking" the device, need to send precise string descriptor requests, and cannot use nut_usb_get_string. But in these cases they are already not using *_simple or *_ascii anyway so this note should not affect the targets as expressed here.