Connect and implement Soil Moisture Sensor

[alrapal]

Description

The code should take into account the SMS and send readings to Adafruit

Acceptance Criteria

• [x] SMS implemented using AnalogSensor class #6
• [x] README.md and Circuit diagrams are updated
• [x] Graceful error handling implemented

blocked by #6

[alrapal]

Done, will be closed when final report is merged