fix(1-hour score graph): 1-hour score graph should display scores computed at fixed intervals (e.g. 1pm-2pm, 2pm-3pm, etc) and not sliding intervals

[yurijmikhalevich]

To make the 1-hour score graph more helpful and consistent, let's compute data points for the graph at fixed intervals instead of sliding window intervals. Currently, because of the sliding intervals, the graph looks different every time you open it.

Let me know if you want to work on the issue or if you have any questions.