Add sessionInfo pubsub topic

[jdpigeon]

We're breaking sessionInfo packets into a different pubsub topic. I've set it up in the app but we need to create the topic and give the neurodoro service account permission to it

[jdpigeon]

Here's the schema for the sessioninfo / streaminfo packets:

{
  "channel_count": 4,
  "manufacturer": "Interaxon",
  "name": "non-symbolic attention",
  "nb_samples": 2723,
  "nominal_srate": 256,
  "session_id": "4yf474451",
  "source_id": "NeuroTechTO",
  "start_time": 1519067445163,
  "type": "RawEEG",
  "uid": "d_shY774yf4",
  "version": "1.0"
}