lay groundwork for a possible future architecture (#1571)

* lay groundwork for a possible future architecture

* switch from feature opt-out to feature opt-in

* lay groundwork for a possible future architecture

* switch from feature opt-out to feature opt-in

* fix USE_RTC in variant.h for rak4631_epaper and t-echo

* ensure Screen.h is not included without configuration.h

Co-authored-by: Peter Lawrence <12226419+majbthrd@users.noreply.github.com>
Co-authored-by: Ben Meadors <benmmeadors@gmail.com>

src/nrf52/main-nrf52.cpp

@@ -161,7 +161,7 @@ void cpuDeepSleep(uint64_t msecToWake)
 {
     // FIXME, configure RTC or button press to wake us
     // FIXME, power down SPI, I2C, RAMs
-#ifndef NO_WIRE
+#if HAS_WIRE
     Wire.end();
 #endif
     SPI.end();