fix(nrf52): add BLE security timeout and advertising watchdog#39

ipduffy wants to merge 2 commits intoweebl2000:nrf52-watchdog-brownoutweebl2000/meshcore:nrf52-watchdog-brownoutfrom

ipduffy:fix/nrf52-ble-stack-hangipduffy/MeshCore:fix/nrf52-ble-stack-hangCopy head branch name to clipboard