1.20.0+keybow.1

Apply keybow customizations

* Remove precompiled USB ETH device
  * CONFIG_USB_ETH
* Enable USB ConfigFS
  * `CONFIG_USB_CONFIGFS=y`
* Enable various ConfigFS network device drivers
  * `CONFIG_USB_CONFIGFS_NCM=y`
  * `CONFIG_USB_CONFIGFS_ECM=y`
  * `CONFIG_USB_CONFIGFS_RNDIS=y`
* Enable ConfigFS HID device functionality
  * `CONFIG_USB_CONFIGFS_F_HID=y`
* Enable network device bonding
  * `CONFIG_BONDING=y`
* Add libusbgx for USB gadget device tools
  * `BR2_PACKAGE_LIBUSBGX=y`