simularium controller maintenance

[interim17]

What needs to happen?

Look at what the controller directly owns, manages, and exposes.

In general move towards a limited, intuitive, documented public API, make it easy for the front end.
"It just should just work."

• remove simularium controller params #466
• move plot data api into ISimulator #477
• move web socket connection down into the remote connected classes and off the controller #480
• add testing to the controller #471
• refine simulator connection params #473
• handle receiving converted file for the front end #472
• add 3rd party url handling to test-bed (and viewer?) #474
• streamline and document controller public API #475

Why should we do this?

When does this need to get done?