Demo WebSocket communication

[statictype]

Have a demo of client - server comms via WebSockets

• how to communicate via channels
• how to query data from preact
• define messages (new transaction, etc.)
• what should be done with WS / what should be done with REST

related to #140

[peetzweg]

A rough flow is demonstrated here:
https://github.com/paritytech/capi-multisig-app/pull/181/files#diff-48a207189b06f0a62ab05a05f02a5f3259b1e28254666b61a078422dde2a1d24R54-R104

@ryanleecode could you maybe give a draft description how you expect the flow and channels be structured?
What channels, which messages, in which order you had in mind?

[peetzweg]

Probably outdated and can be removed?