Add support for scopes

[cereallarceny]

Is your feature request related to a problem? Please describe.
We must allow syft.js to connect to PyGrid. In order to do so, we need to have some concept of a "scope".

Describe the solution you'd like
Scope, as it pertains to grid.js (the only socket library syft.js currently works with), is simply a private "room" where multiple workers can train and predict together. A worker should only ever be a part of 1 scope at a time. Likewise, a scope can include one or many users. This will be mandatory for implementing WebRTC and eventually adding plan and protocol support to PyGrid.

Additional context
Here is some required reading for fully understanding the requirements of this ticket.

In particular, please read the get-protocol section.

[monuelo]

@cereallarceny I'll be working on it. 🤓

[IonesioJunior]

It's yours! :)