Support host controlled bus sync mode via DPM

The host controlled bus sync mode shall be supported. This allows the synchronisation of the host application with CAN bus.

Following points shall be covered:

• Sync Mode is disabled by default to be backward compatible
• use existing generic packet RCX_SET_HANDSHAKE_REQ to configure the sync mode
• use Sync Handshake in DPM
• If host toggles the Sync handshake, the COM Stack will send the SYNC frame on the CAN bus immediatelly and then toggle synchandshake in DPM back.