Update websocket for changed signal structure

[katelyn-chun]

What?

• Updated websocket to normalize new data format

How?

• Mapped the batches in websocket instead of signal-graph-node, for the new 2D array format
• Ensured the entries were in the format of time, signal1, signal2, signal3, signal4
• Changed server.js to send sample data with the new batched format

Test pictures:

Snapshot of backend log:

[MaddieWright]

looks good, good work!