Same functionality as previous commit. But way more stable and clean.
Previous proof of concept approach had issues with random partial or
too large messages due to time based method
Rework send and receive functions to work more stable
- send: encode data with frame (start, end byte)
- receive: read each byte one after the other, assemble message,
handle actual data in handle function
- add semaphore to write operation to prevent parallel write of
different data when called from other tasks
