Rethink the backend architecture

[druskus20]

So ideally:

actual backend with ephemeral ports.

The backend is the one who instructs the tcp task to start receiving.
The backend owns the buffers and communications
When the stream is stopped, the backend cleans up the tcp task
when the tcp task is dropped, the backend notifies the frontend
When the pane is closed, the backend cleans up both the TCP (if active) and the data task.

backend accepts connections on 8080 and promotes them to open ephemeral immediately
the ephemeral task is not ingesting anything unless the UI instructs it to (by clicking connect)

[druskus20]

1. backend registers a new incoming stream
2. backend tells the UI there's a stream ready to open
3. UI opens a new pane, and sends an event to the backend
4. Backend moves the connection to an ephemeral port and opens a new Stream
5. an Stream starts as 1) TCP task and 2) Data task. The data task has access to the shared buffer for the pane
6. backend gives access to the buffer to the UI
7. eventually, TCP stream is closed. TCP task is terminated. Stream is inactive but still contains the data.
8. eventually the UI closes the pane, and a close event is sent to the backend
9. the backend cleans up the stream and frees the data.

How are errors in TCP and DATA tasks handled. They should be immediately reacted to.
Joinset? -> if tcp fails, it's okay, if data fails, it's not