support for CAN-FD and message filters

[mhpetiwala]

Hi - thank you this is a great project. I was looking for something that could publish decoded CAN/CAN-FD messages to MQTT broker as my end goal is to send it out to a webpage.

But my issue is that we're using CAN-FD bus and messages v/s std CAN. The config file supports bus bitrate but not ddrate - I was planning to fork and add that unless you plan to do it. Also another good option would be to support message filters because not all messages in the DBC as well as over the bus may be of interest. Hence was also planning to implement a config param to allow the user to define filters for specific messages/mask based on what is supported by socketcan.

Thank you again for a great project!