sensors: first part of a calibration refactor

This adds uORB messages to publish calibration data by sensors which is
then consumed by the sensors. Currently this is only used on Snapdragon
and guarded by QURT ifdefs.

msg/accel_calibration.msg

@@ -0,0 +1,10 @@
+uint64 timestamp
+
+int32 device_id
+
+float32 x_offset
+float32 x_scale
+float32 y_offset
+float32 y_scale
+float32 z_offset
+float32 z_scale

msg/gyro_calibration.msg

@@ -0,0 +1,10 @@
+uint64 timestamp
+
+int32 device_id
+
+float32 x_offset
+float32 x_scale
+float32 y_offset
+float32 y_scale
+float32 z_offset
+float32 z_scale

msg/mag_calibration.msg

@@ -0,0 +1,10 @@
+uint64 timestamp
+
+int32 device_id
+
+float32 x_offset
+float32 x_scale
+float32 y_offset
+float32 y_scale
+float32 z_offset
+float32 z_scale