Add support for nrf52833

[carrino]

Add support for debug board PCA as well as the bluemicro board. Ideally add support for softdevice 7.2 as well as 6.1.1

[jpconstantineau]

Good news, Adafruit has starting working on getting support for the nrf52833. See this PR: adafruit/Adafruit_nRF52_Arduino#739

Once that is merged, I will be able to get support for the nrf52833 included in the BSP without much issue. (It's just a matter of time)

[h2zero]

Please forgive the promo, I just stumbled across this and thought I'd share an alternative that does not rely on a softdevice or adafruit and supports generic (any nrfx, including 52833) boards using NimBLE. You can check it out here: https://github.com/h2zero/n-able-Arduino