Move to SingalR

[vandycknick]

Remove the custom real time web implementation I was trying to create here: https://github.com/nickvdyck/webtty/tree/master/src/WebTty.Api/Infrastructure . This was good fun and I learned a lot from it, but not maintainable (obviously 🤦). I should be able to swap this out with SignalR.

• Use a strongly typed hub for my terminal abstraction. This should live close to my models in WebTty.Schema (I should consider moving this into something called WebTty.Core and have it contain all core BL for the app.
• Implement streaming via SignalR
• Swap out custom RTM protocol in front end and use SignalR, check if I can still generate code between front end and backend.