change prot function signature to have response mess, and make the payload as pointer to constant buffer
- (uint8_t length, uint8_t const payload[], protMsgResponse_t* mess_response)

rename PROT_CMDTYPE_CMD1 to PROT_CMDTYPE_LED
change protMsgCommand_t, protMsgResponse_t & protMsgError_t to be little-endian & move them to protocol.h
add response message