- Update Schematic
  - remove PUMP_INT connection in Interrupt handler device
- Update source code
  - remove PUMP Interrupt related code
  - add Power Control feature for External Sensors
    - this means the external sensor can be turned ON|OFF by
      turn ON|OFF its power. This is done via the "PUMP_EXT_SENSOR_CTRL", which has the PUMP_EXT_SENSOR_CTRL_I2C_ADDR I2C address