Demonstrate streaming with octopus (Python engine)

[blairlyons]

• [x] https://github.com/simularium/vivarium-models/issues/14
• [x] https://github.com/simularium/simularium-viewer/issues/275
• [x] https://github.com/simularium/octopus/issues/3
• [x] https://github.com/simularium/octopus/issues/1
• [x] https://github.com/simularium/octopus/issues/4

Use Case

As a developer, I want to see simulations streaming from the new Python engine (octopus) to the Simularium viewer, both from pre-computed files and live simulations running in Vivarium.

Acceptance Criteria

• Initial octopus Python engine, deployed in cloud
• Demonstrate streaming data to clients over websockets on request
• Demonstrate streaming data from a pre-computed file
• Demonstrate streaming data from a vivarium simulation
• Test for max concurrent users

[jsavieo]

@toloudis and @blairlyons divide up this milestone to make vivarium a separate story