Dispatch Regional Summary graph data points missing if SCADA data missing

[hnougher]

Noticed today, if the SCADA table is missing data points, the whole graph is missing the data points.

This comes from a required optimisation to explicitly date range the SCADA table lookup for performance.
Specifically this line

NEMView/html/graph/index.php

Line 149 in 0deb398

AND settlementdate_inner >= DATE_TRUNC('hour', NOW() - CAST(:interval AS Interval) + INTERVAL '5 min')

Removing this line solves the problem, but the query takes about 30x longer since it scans the entire SCADA table.

[hnougher]

This has been greatly improved with a TimescaleDB continuous aggregate of the SCADA data.
Halves the SQL time in graph generation compared to before.

But now there ends up being '0' valued data if it does not arrive in time...
I suppose this is better.