Feather nrf52840 is missing the ure module

[dastels]

The ure module is present on the Feather, ItsyBitsy, & GrandCentral, but not on the Feather nRF52840.

[dhalbert]

I'm going to refactor the mpconfigport.h files so we have a common set of features turned on/off across the atmel and nrf ports.

There are some serious differences, including choice of MICROPY_OBJ_REPR (!).

I might do #1434 along with this.

[dhalbert]

Added to nrf builds by #1554. Enhanced by #1544.