nrf: Enable binascii, hashlib modules
nrf: Enable binascii, hashlib modules

These modules would be very handy to have in order to implement a
more robust replacement for ampy.  It costs around 2KiB of text and
no data or bss.

'binascii' has base64 encoding, which can be used to create a fully
8-bit-clean transport above the slightly cooked serial connection of
these boards.

'hashlib' is a bit less critical, but I have found it handy to
be able to robustly checksum remote files.

I see this as only being useful on ports which don't have USB block
device support, so atmel-samd doesn't need it.  These modules are
already on esp8266 so I think nrf52 seems like the only one that
needs it.

adafruit/micropython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/micropython,adafruit/micropython,adafruit/circuitpython,adafruit/micropython,adafruit/circuitpython,adafruit/micropython,adafruit/circuitpython