v2: migrate source and sinks

[ngjaying]

Notice: Please work on master-v2 branch.

In v2, we refactor source/sink interfaces to make it smaller and clearer. Basically, it will meet the Single Responsibility Principle which means source/sink will only handle connection and read/write data. All other activities like batch, data transform(dataTemplate) and serialization are splited as standalone nodes.

This task is to migrate all the sources and sinks in v1.x to v2 by adapting to the new interface. In v2, the source/sink module with the same external system are organized at the same package. So the tasks will be divided according to the IO type.

• [x] Neuron (source, sink, connection)
• [ ] EdgeX (source, sink, connection)
• [x] Http (pull source, push source, rest sink)
• [ ] Redis (sub source, pub sink, sink, connection)
• [ ] Simulator (source)
• [x] SQL (source, sink, connection)
• [ ] ZMQ (source, sink)
• [ ] Kafka (source, sink, connection)
• [x] Video (source)
• [ ] InfluxDB (v1 sink, v2 sink, connection)
• [ ] TDEngine (sink)
• [ ] Image (sink)