I have rewritten parsing logic. Now I parse byte array and try to parse everything I can accourding to zephyr specifications.

Details:
- Data from sensor is now parsed as byte array.
- Extended HeartBeatSensorData to support additional data (distance, stride, speed, firmware, hardware, etc.)
- Logic for parsing header is separeted from logic for payload
- Fixed bug when header is at the start of the package

Known issues:
- Packages of size less than 60 bytes will be likely skipped (header is probably in previous package)
  - This should not present any problems in next package
- Only one message is processed per package
  - In practice you should not get multiple messages in one package for longer period of time
- Heart rate timestamps are not parsed
  - They are not needed and they work inconsistent when package is bigger than 60 bytes.