nrfutil / flashing firmware to Nordic chips

This is an issue to note DFU firmware flash possibility to Nordic Chips (like nRF52) as noted in https://github.com/apache/nuttx-apps/pull/1794#issuecomment-1591769020 when @raiden00pl provided USB Console patch.

* Our help page [1] states that flashing is not possible without a debug probe. This could be done over DFU with nrfutil [2] [3].. at least not that long ago.. when dongle is plugged to USB port RESET switches it to DFU mode :-)
* Nordic abandoned development of the Open-Source utility nrfutil [3] that allowed DFU images generation at version 6. The repository if marked frozen and obsolete, utility does not work anymore on Python 3.8 and 3.9. Even worse they switched to a new utility nrfutil with the same name version 7 that is NOT Open-Source anymore (see comments in [4]) :-( Does this mean that Nordic is limiting Open-Source support for their MCUs?
* Question is DFU image generation is still possible? It would be a great feature for NuttX to quickly flash this device with no debug probes and cables attached. Especially that we will have Console over USB with @raiden00pl patch :-)

[1] https://nuttx.apache.org/docs/latest/platforms/arm/nrf52/boards/nrf52840-dongle/index.html
[2] https://academy.nordicsemi.com/flash-instructions-for-nrf52840-dongle/
[3] https://github.com/NordicSemiconductor/pc-nrfutil
[4] https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/nrf-util-unified-command-line-utility

Start with the nRF52 dongle help page [1] and the linked nrfutil references [2]-[4]. Establish whether available tooling can generate a usable DFU image and what NuttX workflow would own flashing it. Done should be a decided, reproducible DFU path, or a documented limitation with the help page updated accordingly.

Written by the indexing model from the issue text.