Support OTA update for NRF52840

[Crocmagnon]

Is your feature request related to a problem? Please describe.
I’d like to deploy OpenDisplay devices at my parents, and I want to be able to keep the devices updated without spending a Saturday afternoon running around the house with a laptop and a USB cable.

Describe the solution you'd like
Support for OTA updates from Home Assistant to NRF52840 devices.

Describe alternatives you've considered
Running around the house with a laptop and USB cable.

Additional context
None

[jonasniesner]

Hi, we sadly did not manage to get the reliability of OTA Updates for this MCU where we feel comfortable to release it into the HA integration. You still can leave a device unattended without updates though. Except for a few rare and documented cases we try to keep everything backwards compatible. So you don't need to update the device if everything works fine. We should probably also communicate that better