Initiate magnetometer based compass calibration from button presses (#5553)

* Initiate magenetometer based compass calibration from button presses

- only active for BMX160 accelerometers on RAK_4631
- replace automatic calibration on power on with button triggered
  calibration
- set 5 presses to trigger 30s calibration
- set 6 presses to trigger 60s calibration (useful if unit is not
  handheld, ie vehicle mounted)
- show calibration time remaining on calibration alert screen

* Fix non RAK 4631 builds

- exclude changes from non RAK 4631 builds
- remove calls to screen when not present

* Fix build on RAK4631_eth_gw

- exclude all compass heading updates on variant without screen

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Co-authored-by: Ben Meadors <benmmeadors@gmail.com>

src/motion/BMX160Sensor.h

@@ -23,6 +23,7 @@ class BMX160Sensor : public MotionSensor
     explicit BMX160Sensor(ScanI2C::FoundDevice foundDevice);
     virtual bool init() override;
     virtual int32_t runOnce() override;
+    virtual void calibrate(uint16_t forSeconds) override;
 };
 
 #else