Since there are no more users and dependencies of
Kconfig option USB_UART_CONSOLE in the tree,
remove the remains and the option USB_UART_CONSOLE.
Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>
This change organizes the file structure for the shell.
Files implementing backends are moved to a separate folder.
Signed-off-by: Jakub Rzeszutko <jakub.rzeszutko@nordicsemi.no>