[CanProtocol] Created encode/decode functions for PressureData and TemperatureData, added enqueueSimplePacket() to send a packet with a manually crafted payload

Changes:
- Fixed casting errors and made conversions more explicit
- Fixed offset, gain and PGA configuration when performing a self test or an offset calibration
- Moved magic numbers in a separate Defs files

This would cause a configuration reset when starting the sensormanager!